Synthesis Example

C5H4O3 -> [C +] C4H4O3
Under irradiation with visible or UV (>290 nm) light in the presence of molecular oxygen and a minute amount of fullerenes, olefins and dienes undergo ene and Diels-Alder reactions with singlet oxygen to give photooxygenation products. The regio- and ster oselectivities of the photooxygenation of beta-myrcene, (+)-pulegone, 4-methylpent-3-en-2-ol, and (+)-limonene were very similar to those observed in known singlet oxygen reactions, indicating that the fullerene-sensitized reaction generates free singlet xygen. The efficiency of fullerenes and conventional sensitizers was qualitatively examined by using the Diels-Alder reaction between O-1(2) and furan-2-carboxylic acid as a probe. Among those examined, C-70 was found to be the most effective. The reactio was the fastest and completed with as little as 0.0001 equiv of C-70. C-60 and hematoporphyrin were found to be of similar efficiency. The methanofullerene 13, which lacks one olefinic conjugation in the C-60 core, was as good as C60 itself, but the amin fullerene 14, lacking six double bonds, was quite inferior. The fullerene carboxylic acid 15, which was previously shown to show considerable biochemical activity, was found to be capable of generating singlet oxygen in aqueous DMSO.

C20H16ORuR [+ R] -> C20H16ORuR2
Five metallaindene complexes of molybdenum, tungsten, and ruthenium (3a (Mo), 3b (W), 3c (Ru), 5a (Ru), and 5b (Ru)) have been prepared. The complexes of molybdenum and tungsten show fluxional behavior for which a pseudorotation mechanism is suggested. Re ction of the ruthenium complex 3c with phenyllithium or p-tolyllithium followed by CF3SO2OSiMe3 gives aryl substituted ruthenaindenes 5a and 5b. In solution, these complexes quantitatively rearrange to form ruthenocene derivatives 11a and 11b. A mechanism for this rearrangement which includes a series of carbonyl and carbene insertions is proposed. Crystallographic data for 3b: P2(1)/n, a = 9.945(2) angstrom, b = 13.207(2) angstrom, c = 11.304(2) angstrom, alpha = 90-degrees, beta = 107.38(2)-degrees, gamm = 90-degrees, Z = 4. For 5a: P2(1)/n, a = 9.082(1) angstrom, b = 10.601(1) angstrom, c = 16.827(2) angstrom, alpha = 90-degrees, beta = 92.57(l)-degrees, gamma = 90-degrees, Z = 4. For 11b: P2(1)2(1)2(1), a = 8.452(1) angstrom, b = 12.558(1) angstrom, c 15.812(2) angstrom, alpha = beta = gamma = 90-degrees, Z = 4.

C9H9NO + C5H4FN -> [FH +] C14H12N2O
The reactions of the sodium salts of indoles with 2- and 4-fluoropyridines afforded the corresponding N-pyridylindoles in good yields, whereas the reaction with 3-fluoropyridine gave no coupling product.

C16H17F6NO6S2 -> [CHF3O3S +] C15H16F3NO3S
Vacuum thermolysis of various 3-trifloxypropene iminium triflates 1 leads to propyne iminium triflates 2 by beta-elimination of triflic acid. In contrast, salt 1j undergoes an intramolecular aromatic S(E) reaction.

C16H20FN3O3S -> [H2 +] C16H18FN3O3S
The 3,5-diaminoisothiazole derivatives 23-42 were synthesized in excellent yields by oxidative cyclization of 3-amino-3-(dialkylamino)propenethioamide derivatives. These intermediates and the isothiazole derivatives were tested in vitro for their antimicr bial activity.

C5H5NO + C7H7Br -> [BrH +] C12H11NO
Alkylation of 2-pyridone has been performed in solvent-free conditions. The effect of base, phase transfer agent, and alkylation agent has been discussed.

C11H15N5O3S [+ O] -> [HN +] C11H14N4O4S
Adenosine derivatives lacking a 5'-hydroxyl group seldom act as alternative substrates of adenosine deaminases from calf intestine and other mammalian sources. A deaminase from Aspergillus oryzae deaminated adenosine 5'-thioether derivatives cleanly and m re efficiently than alkyl nitrites. The inosine derivatives were very poor alternative substrates and weak inhibitors of purine nucleoside phosphorylase.

C7H6O + C7H14O -> [H2O +] C14H18O
Alpha-n-amylcinnamaldehyde (jasminaldehyde) was obtained with 82 % yield by solid-liquid phase transfer catalysis without solvent within 3 days at room temperature. By use of domestic microwave irradiation, the same yield was obtained within 1 minute at a power of 600 W.

C8H7Cl [+ O] -> C8H7ClO
Mn(iii)-tetraarylporphyrins bearing either a heterocyclic nitrogen base axial ligand or a carboxylic acid group, or both, covalently bonded to the porphyrin through a single flexible chain, have been synthesized. Their basic frame is that of the robust te rakis(2,6-dichlorophenyl)porphyrin, and the chains are connected by ether or amido linkages to the ortho-positions of one meso-aryl group. Catalytic efficiency was tested in alkene epoxidations at 0-degrees-C under aqueous CH2Cl2 two-phase conditions in t e presence of NaOCl (pH 10.5) or 30% H2O2 (pH 4.5) as oxygen donors (ODs). Compound 4 bearing an imidazole ligand showed satisfactory catalytic activity in the presence of both ODs, whereas Mn(III)-porphyrins 5a-d bearing a covalently bonded carboxylate g oup are suitable for the activation of H2O2, and proved to be very efficient in the presence of an externally added axial ligand. Catalyst 6, featuring an imidazole ligand and a carboxylate group bonded on the 2,6-positions of the same meso-aryl group, is particularly efficient in alkene epoxidations promoted by 30% H2O2 (initial rates up to 500 turnovers/min, overall turnovers up to 1200). A possible reaction mechanism for epoxidation catalysed by the bis-tailed Mn(iii)-porphyrins is discussed.

C6H6O2 [+ C4H4N2] -> C10H10N2O2
A series of 4,5-diamino-substituted-1,2-benzoquinones were prepared from catechol and the corresponding secondary amines in high yield in a single step using copper complex formation to stabilize the intermediate. The cytotoxicity of the products under va ious conditions was evaluated using the EMT-6 mammary carcinoma cell line, and antitumor activity was tested in the L1210 murine leukemia. The 4,5-diaziridinyl-1,2-benzoquinone was a more potent cytotoxic agent than diaziquone (AZQ) and was very effective against the L1210 leukemia. The azetidine, pyrrolidine, and diethylamine derivatives were not effective antitumor agents.

C21H34O2 [+ H2] -> C21H36O2
The direction of reduction of 20-carbonyl group of 3alpha-hydroxy-5beta-pregnan-20-one (1) with a complex of borane-methyl sulfide and chiral beta-amino alcohols, depends on the chirality of the amino alcohol. Where there is a 2-phenyl or 2-benzyl substit ent, then the S enantiomer gives exclusively the steroid 20R alcohol 3. The R enantiomer of 2-amino-2-phenyl-1-ethanol gives the highest steroid 20S (2):20R (3) alcohol ratio.

C7H10 [+ H2] -> C7H12
Diimide is a well-known reagent for hydrogenating multiple bonds with very high stereospecificity. However, all of the methods for generating diimide require somewhat rigorous conditions. We show here that 1-thia-3,4-diazolidine-2,5-dione (TDADH) can be u ed to photochemically produce diimide at room temperature under neutral conditions. The diimide thus produced can hydrogenate multiple bonds in high yields.

C24H24O4 -> C24H24O4
Anchoring two acryloyl substituents onto a paracyclophane:skeleton generates four 'cinnamophane' isomers. one of which, the pseudo-gem, undergoes a 'topochemical' reaction in solution.

C21H42O3Si -> [C5H8O +] C16H34O2Si
A mild method for selective cleavage of tetrahydropyranyl ethers in the presence of other acid sensitive functionalities such as acetonides, methoxymethyl ethers, methylenedioxy ethers, mesitaldehyde acetals and t-butyldimethylsilyl ethers using Lewis aci -thiol system is described.

C31H36O5S [+ O2] -> C31H36O7S
Several sulfides have been converted to sulfoxides or sulfones in modest to excellent yields. The oxidant was oxone(R) and the reactions were performed in 12.5% aqueous acetone and buffered to pH 7.5 - 8.0 with sodium bicarbonate.

C16H22O11 + C3H9N3Si -> [C5H12O2Si +] C14H19N3O9
In the presence of a catalyst generated from SnCl4 and AgClO4, or Yb(OTf)(3), various glycosyl azides are synthesized in high yields with complete stereoselectivities from peracylated sugars and trimethylsilyl azide by choosing a suitable solvent such as ichloromethane or nitromethane.

C33H26O2S2 -> C23H20O2 + C10H6S2
Naphthalene-1,8-dithiol reacted with aldehydes to give dithioacetals which were oxidized to 2-substituted naphtho(1,8-de)1,3-dithiin-1-oxides (4). 2,2-Disubstituted naphtho(1,8-de)1,3-dithiin-1-oxides (5) were obtained on treatment of 4 with NaH/electroph les. Photolysis of 4 and 5 undergoes intramolecular oxygen rearrangement to generate aldehydes and ketones quantitatively together with naphthalene-1,8-dithiole.

C7H4BF7N2O -> [BF3N2 +] C7H4F4O
The fluoro-dediazoniation of ArN2BF4 using HF-pyridine solution has been successfully carried out either thermally or photochemically to afford the corresponding ArF in good yields. Particularly, the photochemically induced reaction in HF-pyridine was a u eful tool for the preparation of ArF having polar substituents such as halogens, OH, OMe, CF3, etc.

C35H30O9S + C34H36O6 -> [CH4S +] C68H62O15
A new method to activate thioglycosides is described. The combined use of PhSeNPhth and TMSOTf was demonstrated to be a powerful promoter of thioglycoside. The reaction proceeds rapidly even at low temperature to give O-glycoside in a high yield. The effe ts of solvents and reaction temperature were also investigated.

C7H14OS + C8H8OS -> C15H22O2S2
New ring-opening reaction of thiiranes with carboxylic acid derivatives having good leaving groups was investigated. The reaction of thiiranes with acyl chlorides or S-aryl thioesters using quaternary onium salts as neutral catalysts proceeded very smooth y and regioselectively to afford the corresponding S-thioesters as addition products.

C7H9N + C10H12O2 -> [H2O +] C17H19NO
Aldehydes (4 eqiv.) react under mild conditions with LiAl(NHR1)4 (1 eqiv.) to give the corresponding imines in 90% yield and no polymerization was observed upon reaction of aliphatic aldehyde 3.

C12H22O2 [+ O] -> [CH2 +] C11H20O3
Photoexcited p-dimethoxybenzene catalyses oxidative cleavage of various alkenes to corresponding carbonyls in the presence of oxygen.

C8H6O2 + C16H14O3 [+ X2] -> [H4O2 +] C24H16O3X2
Poly(chalcone)s were prepared by polycondensation of aromatic dialdehydes with aromatic diacetyl compounds in methanesulfonic acid (MSA) or phosphorus pentoxide/methanesulfonic acid (PPMA). Polycondensations proceed smoothly at room temperature and produc d poly(chalcone)s with inherent viscosities up to 0,97 dL . g-1. The reaction of acetophenone with aromatic aldehydes in MSA or PPMA was studied in detail to demonstrate the feasibility for polymer formation. Poly(chalcone)s are only soluble in concentrat d sulfuric acid and methanesulfonic acid at room temperature. Thermogravimetry of poly(chalcone)s showed 10% weight loss around 380 and 420-degrees-C in air and under nitrogen, respectively.

C2H4O [+ H2] -> C2H6O
Electrochemical reduction of formaldehyde to methanol, acetaldehyde to ethanol, and acetone to 2-propanol has been achieved using either one of the two kinds of alcohol dehydrogenases, ADH(EC1.1.1.1) and ADH(EC1.1.1.2), as an electrocatalyst. ADH(EC1.1.1. ) was effective in reducing formaldehyde at a relatively high reaction rate, while ADH(EC1.1.1.2) worked well for the reduction of acetaldehyde and acetone. In all cases the current efficiency and the production yield attained to ca. 100%.

C7H6O2 + C7H8O -> [H2O +] C14H12O2
Cyanomethylenetributylphosphorane was shown to mediate the direct condensation of alcohols with O- and N-nucleophiles. A secondary alcohol, 2-octanol, reacted satisfactorily with Walden inversion of its carbinyl carbon.

C3H5ClO + C18H40SiSn -> [C12H26Sn +] C9H19ClOSi
Terminal epoxides react with 2-(trialkylsilyl)allyl organometallics (Sn, Si, Li, Cu) with varying degrees of efficiency depending upon the nature of the epoxide. The combination of (2-(trimethylsilyl)allyl)tributylstannane (4) and EtAlCl(2) is optimum and provides 1-substituted 4-(trimethylsilyl)-4-penten-1-ol products in good yield.

C19H26O2S -> [C6H4O2S +] C13H22
An extremely convenient desulfonylation method of primary, secondary, tertiary alkyl and vinyl phenyl sulfones was developed by using magnesium in ethanol in the presence of catalytic amount of mercuric chloride to give the corresponding alkanes and alken in almost quantitative yields.

C14H18N2O7 [+ CH2N2] -> C10H14N2O5 + C5H6N2O2
Lipase catalyzed deacetylations of anomeric mixtures of peracetylated 2'-deoxyribofuranosyl- and 2'-deoxyribopyranosyl thymine nucleosides 1 and 5 have been investigated. Generally, the diastereoselectivity was more pronounced in pure phosphate buffer tha in phosphate buffer containing 10% DMF. Wheat Germ Lipase and Porcine Liver Esterase catalyzed diastereoselective deacetylation of 1 affording the pure beta-anomer thymidine (4 beta) as the only completely deprotected nucleoside product.

C16H34O + C2H4ClO2P + C3H9N [+ O] -> [ClH +] C21H46NO4P
A high-yielding, 3-step, one-pot conversion of lipid hydroxy accepters 2 into clinically useful alkylphosphocholines 1 is reported. Reaction of 2 with ethylene chlorophosphite gave phosphite 3, which underwent oxidation and ring opening with bromine in CH Cl2 to give (2-bromoethyl)phosphate ester 4; hydrolysis of the P-Br bond and quaternization of 4 with aqueous trimethylamine generated 1.

C7H12 + C7H12BrNO [+ H] -> [Br +] C14H25NO
A new method for the synthesis of conjugated dien- and enamides by pallladium-catalyzed coupling reaction of (E)-beta-bromo-acrylamides with alkenyl- and alkylboronates is reported. This procedure provided some biologically active, naturally occurring uns turated amides, such as dehydropipemonaline, pipernonaline and other related alkaloids, in one-pot.

C29H22 + C33H64Ba2N2O2Si4 -> [C13H30Ba2N2OSi4 +] C49H56O
Reaction of two equivalents of C(5)Ph(4)H(2) With Ba(N(SiMe(3))(2))(2)(THF)(2) in THF or toluene-produces the solvated octaphenylbarocene (C(5)Ph(4)H)(2)Ba(THF) in quantitative yield. The air-sensitive metallocene displays a surprising lack of thermal sta ility, and decomposes in the solid state at room temperature over a period of two weeks or upon attempted vacuum sublimation at 110-120 degrees C (10(-6) torr). Reaction of C(5)Ph(4)H(2) with Ba(N(SiMe(3))(2))(2)(THF)(2) in a 1 : 1 molar ratio in THF or t luene produces a yellow solid that is a mixture of the metallocene with the mono(ring) compound (C(5)Ph(4)H)BaN(SiMe(3))(2)(THF)(n). Attempts to synthesize a barocene containing the pentapbenylcyclopentadienyl ligand were not successful.

C7H6O + C9H18Sn -> [C3H8Sn +] C13H16O
The title reaction affords non-conjugated 1,4-dienes with high regioselectivity especially in a donating solvent at ambient temperature under acidic conditions without special protection from air and moisture.

C7H6Br2 + C11H16O3 [+ O] -> [CH2Br2 +] C17H20O4
When conjugated dienic side chain of abscisic acid is substituted with 3-carboxyl-5-methylphenyl group, the product shows abscisic acid-like activity. We developed one pot synthetic pathway of it, which was optically resolved with chiral HPLC column.

C8H7N + C2H2Cl2O [+ C16H11N2] -> [Cl +] C26H20ClN3O
A one-pot synthesis of some novel indolylquinoline analogues of biological interest using indole or its 5-substituted derivatives as substrates under Friedel-Crafts acylation conditions is reported. The synthesis of the compounds was accomplished by the e ployment of excess amounts of the substrates and higher temperature. The complete structure of the derivative obtained by using indole as substrate and dichloroacetyl chloride as acylating agent was unequivocally established as 2-(2"-dichloroacetamidobenz l)-3-(3'-indolyl)-quinoline 2a by single crystal X-ray analysis. The structures of other similar indolylquinolines 2b-2e and 3 were defined by spectroscopic analysis. The mechanism of formation of the analogues has also been rationalised.

C8H10O3 + C5H8O -> [H2O +] C13H16O3
The reaction of a phenol, an alpha, beta-unsaturated aldehyde, and phenylboronic acid yields a 2-phenyl-4H-1,3,2-benzodioxaborin. Upon heating, this compound decomposes to an orthoquinone-methide intermediate, which undergoes an electrocyclization reactio to a chromene ring system. This method has been applied to the synthesis of precocenes I and II and the robustadial A and B.

C25H27N3O4S [+ H2] -> C25H29N3O4S
Addition of isopropanol to the stoichiometric reduction of ketones 4-8 using oxazborolidine-borane complex 3 or the oxazaborolidine-catalyzed reduction of 4-chromanone analogs (1, 7-9) enhances the enantioselectivity of the reduction.

C16H11N5 [+ H2] -> [N2 +] C16H13N3
Azidopyrazines do not undergo reduction by reagents that are effective for the preparation of alkyl- or arylamines from the azides because the heterocyclic azides exist in the bicyclic form of tetrazolo(1,5-a)pyrazines. Nevertheless, the conversion into a inopyrazines was achieved by hydrogenolysis in the presence of ammonium hydroxide and palladium-on-carbon or particularly by reduction with tin(II) chloride in methanolic hydrochloric acid, in 34-87% yields. To elucidate the successful progress of the rea tion, the equilibrium of azide-tetrazole was examined by H-1 NMR spectroscopy in various solvents.

C19H24O3 + C8H12O8Pb -> [C6H10O6Pb +] C21H26O5
2,2-Dimethylandrost-4-ene-3,6,17-trione (5) and its 4-methoxy- (7) and 4-hydroxy- (8) derivatives were synthesized. 7 alpha-Acetoxy-4-ene-3,6-dione steroid 2 was also prepared by the improved method involving (11 and 12), 2-substituted 1-ene- (9 and 10), nd 4-substituted (13-15) derivatives of compound I were the 2 beta-acetate 11 of which K-i values were not determined because of their pool inhibitory activities, blocked aromatase in a competitive manner. Compounds 5 and 8 as well as the 4-hydroxy steroi 15 were potent inhibitors (K-i: 25-42 nM) whereas the inhibitory activities of steroids 2, 7, 9, 13, and 14 were good to fair, respectively (K-i: 160-810 nM). Inhibitors 2 and 15 inactivated the enzyme in a time-dependent manner in the presence of NADPH ut the 2,3-dimethyl derivatives 5 and 8 did not. Androstenedione blocked the aromatase-catalyzed oxygenation at C-19 of the dimethyl steroids 5 and 8 most likely through the steric reasons.

C12H8O2S [+ H2] -> [O2S +] C12H10
Photolysis of dibenzothiophene sulfoxide in isopropanol provides biphenyl in quantitative yield via two sequential photochemical reactions. Mechanistic aspects of the reaction are discussed, including the unusual observation that isoprene increases the qu ntum yield of loss of starting material.

C23H18N2O2 -> [CO2 +] C9H9N + C13H9N
irradiation of a molecular crystal between phenanthridine and 3-indoleacetic acid at -70 degrees C causes decarboxylation to give 3-methylindole in high yield as the sole product; phenanthridine:behaves like a stoichiometric sensitizer in the crystal.

C15H27IO2 [+ H] -> [I +] C15H28O2
When the photostimulated cyclization reaction of omega-iodoalkylacrylates was performed in the presence of metal hydride complexes such as sodium cyanoborohydride(NaBH3CN), sodium borohydride(NaBH4) and potassium borohydride (KBH4), the corresponding macr cyclic lactones were produced. The use of NaBH3CN led to the highest yield of lactones.

C6H9Br2ClO [+ C2H6S] -> [Br2 +] C8H15ClOS
When alpha,alpha-dibromomethyl ketones are treated with sodium thiolates only the alpha-monosulfenylated ketones are formed. Evidence is put forward that the reaction mechanism proceeds by an initial nucleophilic substitution of one bromo atom and reducti n by single electron transfer (SET) - hydrogen atom abstraction of the second bromo atom.

C19H22O3 [+ C19H22O5] -> C19H22O4 + C19H22O4
Geranylacetone and geranyloxycoumarin (aurapten) were investigated with 14 selected microorganisms for omega-hydroxylation and epoxydation of the subterminal double bond. Trichoderma koningii and Verticillium theobromae are in principal useable for both eactions of geranyacetone. Although the yields of these preferably intended reactions were low, while omega-1-, omega-3-, omega-4-hydroxylations partially combined with reductive side reactions take place, the results gave an insight in the different pat ways of oxidations dependent on the microorganism used. In contrast aurapten is transformed in relatively high yield to the E- or/and Z-configurated omega-alcohols (auraptenols) and to the aurapten-6,7-epoxide. The exclusively useable microorganisms for the oxidation of aurapten selected from the 237 strains tested were Nocardia alba and Bacillus cereus, which both formed enantioselectively the naturally configurated epoxyaurapten R-(+)-(6',7'-epoxy-3',7'-dimethyl-2' octenyl)-7-oxycoumarin in yields of 1 ,5% respectively 21% of excellent optical purity of 99%ee.

C3H6N4S + C8H6O3 -> [H2O +] C11H10N4O2S
Considerable increase in the reaction rate has been observed with better yields in the syntheses of some substituted 5, 6-dihydro-s-triazolo(3, 4-b) (1, 3, 4) thiadiazoles by the condensation of 3-alkyl/aryl-4-amino-5-mercaptotriazoles (1) with various ar matic aldehydes (2) in the presence of catalytic amount of p-toluenesulphonic acid in unsealed vessels by microwave irradiation using DMF as energy transfer medium.

C7H6O + C6H11BrO2Zn [+ H] -> [BrZn +] C13H18O3
The cheap commercially available (1S,2S)-1-phenyl-2-amino-1,3-propanediol 2 appears to be a convenient precursor for the synthesis of chiral auxiliaries for the preparation of optically active beta-hydroxy esters by asymmetric Reformatsky reactions. The N N-dimethyl derivative of TBDMS-2 gave products with enantiomeric excesses up to 65 %.

C22H26F2N2O2 [+ C20H24F2N2O] -> C20H24F2N2O + C22H26F2N2O2
alpha-(3-Chloropropyl)-4-fluorobenzenemethanol, a possible intermediate for synthesis of a potential anti-psychotic agent alpha-(4-fluorophenyl)-4-(5-fluoro-2-pyrimidinyl)-1-piperazine butanol (BMS 181100), was resolved by acetylation using isopropenyl ac tate and lipase PS-30 in heptane. S-alcohol was obtained in 42% yield with >99% optical purity. R-acetate was obtained with 92.6% optical purity by stopping the reaction after 46% conversion. The enzymatically produced acetate was hydrolyzed by lipase PS- 0 to give R-alcohol with >99% optical purity after 62-72% conversion. BMS 181100 acetate ester was treated with lipase GC-20 in buffer containing 10% toluene to give the R-alcohol with 97.9% optical purity after 47.6% conversion. The rate and enantioselec ivity of hydrolysis by lipase GC-20 were very dependent on the organic solvent. E values ranged from 1 in the absence of organic solvent to >100 with dichloromethane and toluene.

CH3NO2 [+ CCl] -> [N +] C2H3ClO2
A novel synthesis of chloroformate was developed by palladium-catalyzed reaction of XCl (X = H or NO), CO, and alkyl nitrite in the gas phase. When PdCl2/gamma-Al2O3 or PdCl2/SiO2 was used as a catalyst, chloroformate was produced in good yield and with igh selectivity. The reaction temperature had a strong influence on the formation rate of chloroformate, and its selectivity drastically depended on the nitrite/chloride ratio. When the nitrite/chloride ratio was less than 2, the selectivity of chlorofo mate was almost 100%. Dependence of the formation rate on the concentrations of CO and methyl nitrite was also examined.

C24H28OSi -> [C16H18Si +] C8H10O
Hindered silylated ethers such as t-butyldiphenylsilyl or triphenylsilyl are readily cleaved at room temperature using in situ generated HF from the reaction of BF3.OEt2 with 4-methoxysalicylaldehyde.

C6H13NO2 [+ CO] -> C7H13NO3
A variety of amino acid ester hydrochlorides react with triethyl orthoformate (TEOF) or trimethyl orthoformate (TMOF) to give the N-formyl amino acid ester in good yield and high optical purity.

C10H10 [+ O] -> C10H10O
Diphenylphosphinic anhydride and certain other organophosphorus electrophiles mediate the high-yield conversion of alkenes to epoxides by hydrogen peroxide in buffered aqueous tetrahydrofuran.

C19H14O3 -> [H2O +] C19H12O2
Irradiation (using pyrex glass filter) of o-hydroxybenzoylacetophenone (1a), o-hydroxybenbzoylacetone (1b), 2-hydroxy-1-naphthoylacetophenone (5a), 2-hydroxy-1-naphtloylacetone (5b) and 1-hydroxy-2-naphthoylacetone (9) in Br2/CHCl3 and I2/MeOH solutions l ads to various chromone derivatives. Parallel reactions of these 1,3-diketones in the dark record no perceptible change in them. Enhanced photoenolisation of the diketones, in the presence of bromine or iodine, is deemed to be the key step in these tran formations.

C28H24O10 + C11H22N2O2Si2 -> [C8H20O3Si2 +] C31H26N2O9
Several beta-D-ribonucleosides are stereoselectively synthesized in high yields from methyl 2,3,5-tri-O-benzoyl-beta-D-ribofuranosyl carbonate and trimethylsilylated nucleoside bases such as pertrimethylsilylated uracil and adenine under mild conditions b using a catalytic amount of tin(II) chloride, a weak Lewis acid.

C9H9NO2 + C3H5BrMg [+ H] -> [BrMg +] C12H15NO2
Reactions of RMgX-CeCl3 complexes with nitroenes lead to functionalized nitroalkanes in very good yields.

C10H11N5O3 [+ O] -> [HN +] C10H10N4O4
Adenylic acid deaminase from Aspergillus niger (AMP deaminase; AMPDA; EC 3.5.4.6) has been introduced as a novel practical catalyst in the synthesis of 6-oxopurine riboside and their analogs. This enzyme has a very broad substrate specificity and has been used on a preparative scale for deamination of several derivatives of adenosine including phosphorylated, cyclic, carbocyclic as well as acyclic analogs. In addition, AMPDA catalyzes dechlorination and demethoxylation of the purine ribosides. Overall subs rate specificity of AMPDA is much broader than that of adenosine deaminase which can also be used for the synthesis of 6-oxopurine ribosides. Although the stereoselectivity of AMPDA is modest, this enzyme has successfully been used in the synthesis of a n vel antiviral agent, carbovir phosphonate (14), after the carbocyclic component was resolved via lipase-catalyzed hydrolysis or acylation.

C13H19ClOSi [+ S] -> [ClHO +] C13H18SSi
Haloacylsilanes 1a-d were transformed by H2S/Cl into the corresponding silyl thiones 2 which underwent enethiolization on base treatment. Enethiols 3 cyclized intramolecularly to afford the title compounds 4a-d in high yields.

C3H6O + C7H6O [+ C7H2] -> [O +] C17H14O
Various chalcones and related enones have been synthesised in unsealed vessels in a domestic microwave oven. Considerable increase in the reaction rate has been observed with better yields.

C8H8O [+ H2] -> C8H10O
beta-Amino alcohols derived from L-valine were used as chiral ligands in oxazaborolidine reductions of ketones. Structural modifications, such as the introduction of alkyl groups on the carbinol carbon and the nitrogen atoms, were shown to influence unfav urably the enantioselectivity. In contrast, the addition of diethyl zinc to aldehydes occurs with enhanced e.e.'s using these modified inductors, which permit to reach useful enantioselectivities with various aldehydes.

C12H16OSTe + C3H9ClSi [+ Si] -> [CHClTe +] C14H24OSSi2
Tellurol esters having an anion stabilizing group at the position alpha to the carbonyl, such as aryl-, (phenylthio)-, and (benzyloxy)ethenetelluroates, gave enol silyl ethers of the corresponding acylsilanes in good to excellent yields upon treatment wit 2 equiv of (n)BuLi in the presence of chlorosilanes. This reaction was stereoselective, and Z-isomers were obtained as sole or major products from a variety of chlorosilanes, such as trimethyl-, triethyl-, dimethylphenyl-, and tert-butyldimethylsilyl chl rides. Control experiments revealed that the reaction comprises the following consecutive processes: (i) alpha-proton abstraction, (ii) chlorosilane-trapping, (iii) lithium-tellurium exchange, (iv) 1,2-silyl migration, and (v) chlorosilane-trapping. Intra olecular rearrangement of (alpha-siloxyvinyl)lithiums to lithium enolates (step iv) was very fast even at -105 degrees C, and the former could not be trapped intermolecularly either with acetic acid or with coexisting trimethylsilyl chloride.

C10H11ClO3 [+ C9H9ClO3] -> C9H9ClO3 + C10H11ClO3
Crude lipase from Candida rugosa (CRL) is a poorly to moderately enantioselective catalyst for the hydrolysis of esters of 2-substituted carboxylic acids such as 2-arylpropanoic acids (E = 4-10) and 2-(aryloxy)propanoic acids (E = 2-17). Previous workers onverted CRL into a high enantioselectivity form using a four-step purification procedure that included an organic solvent treatment. In this paper we report a simple 2-propanol treatment that converts crude CRL to the high enantioselectivity form. Dissol ing crude commercial CRL in 50% 2-propanol followed by dialysis to remove 2-propanol increased the total activity by a factor of 1.2-1.6 and the enantioselectivity toward seven carboxylic acids by a factor of 2.3 to >25. We demonstrated synthetic use of t is 2-propanol-treated CRL by resolving 10 g of methyl 2-(4-chlorophenoxy)propionate (3-methyl ester), yielding 2.8 g of product acid (93.1% ee R, a serum cholesterol-lowering compound) and 4.7 g of recovered ester (94.4% ee S), corresponding to an enantio eric ratio of 100 for the resolution. Recent X-ray crystal structures identified two conformational forms of CRL-open and closed. We suggest that the 2-propanol treatment may increase the activity and enantioselectivity by converting the closed form of CR to the open form.

C22H31ClO4 [+ Cl] -> [HO +] C22H30Cl2O3
Gaseous hydrogen chloride reacts directly with crystalline 17-hydroxy-20-ketosteroids like 17 alpha-hydroxy-progesterones (1, 5, 6, 8) to give enlargement of ring D. In addition to the known acyloine rearrangement, new reaction types are observed which gi e rise to the products of substitutive rearrangement with elimination of water. 16 beta-Chloro-(3) and 16 alpha-chloro-16 beta-methyl-17-oxo-D-homosteroids (7, 9) are formed stereoselectively. The drying agent magnesium sulfate may keep the reaction produ ts solid. Mechanistic proof is provided spectroscopically (IR) and by the isolation of 17a beta-hydroxy-17a alpha-methyl-D-homeandrost-4-ene-3,17-dione (2) and its conversion to 16 beta-chloro-17a beta-methyl-D-homoandrost-4-ene-3,17-dione (3) with gaseou hydrogen chloride. The new reaction types do not occur in solution.

C9H9ClX2 [+ H2N] -> [Cl +] C9H11NX2
A one-pot synthesis of various primary amines is described. Potassium 1,1,3,3-tetramethyldisilazide, prepared from 1,1,3,3-tetramethyldisilazane and potassium hydride, reacts with alkyl bromides, iodides, tosylates, benzylic chlorides, and allylic chlorid s to give the corresponding N,N-bis(dimethylsilyl)amines in high yields. Subsequent deprotection of the dimethylsilyl group was performed under mildly acidic conditions to afford primary amines. This method was also applied to the preparation of aminometh lated cross-linked polystyrene.

C18H34 [+ H2O] -> C18H36O
Calcium borohydride is found to hydroborate unsaturated systems in the presence of ethyl acetate. The reaction exhibits remarkable selectivity towards terminal double bonds. Several Z-11-alken-1-ol pheromones are synthesized using this method.

C10H16 [+ O] -> C10H16O
Water-soluble manganese(III) as well as iron(III) porphyrinates are introduced as light-sensitive precursor compounds for the photocatalytic activation of dioxygen in aqueous solutions. It is shown that in the presence of alpha-pinene (4) and the further ycloalkenes 11-13 photocatalytic oxygenation reactions occur. The dependence of the selectivity of the oxygen transfer to the olefin on both the presence of water and the variation of the substrate-to-catalyst ratio is discussed. The catalyst may be conve iently separated from the substrates/products by using aqueous solvent systems.

C60 + C7H16O2Si -> [C3H8Si +] C64H8O2
The photochemical catalysis of carbon-carbon bond formation of C-60 with ketene silyl acetals is described to give a new way for fullerene functionalization chemistry.

C8H8 [+ BrH] -> C8H9Br
The synthesis of (2-bromoethyl)benzene by the anti-Markovnikov addition of gaseous hydrogen bromide to styrene has been found to be promoted by alpha-bromo carbonyl compounds such as 2-bromo-2-methylpropanal. These compounds were found to catalyze the "ab ormal" addition in a variety of solvents such as ethyl acetate, heptane, toluene and dioxane. High concentrations of 2-bromo-2-methylpropanal and hydrogen bromide and low concentrations of styrene favor formation of (2-bromoethyl)benzene. Using the free-r dical catalyzed cyclization of 6-bromo-1-hexene as a probe we have found that the 2-bromo-2-methylpropanal does not in itself initiate a free-radical chain reaction by thermal formation of radicals. Instead, radicals may react with 2-bromo-2-methylpropana to form relatively stable 2-methylpropanal radicals. The presence of such radicals increases the effective length or inhibits termination of the free-radical chain reaction (propagation) and in the case of hydrobromination of styrene raises the yield of 2-bromoethyl)benzene.

C7H5NO3 [+ H2] -> C7H7NO3
A new variation of the Meerwein-Ponndorf-Verley reduction based on mechanistic considerations is presented. Under optimized conditions 1-(4-dimethylaminophenyl)ethanol was used as the reducing alcohol (2-4 equiv.), Zr(O-tBu)(4) as the catalyst (0.2 equiv. and toluene or cyclohexane as the solvent. Aldehydes and ketones (if not extremely sterically hindered) were reduced to the corresponding alcohols at room temperature mostly within 2-4 h in essentially quantitative yield. alpha,beta-Unsaturated carbonyl ompounds cleanly react in a 1,2-mode to afford the corresponding allylic alcohols.

C7H14O + C7H5ClO -> [C7H3ClO +] C7H16O
Diisopinocampheylchloroborane(Ipc2BCl) exhibited remarkable chemoselectivity for the reduction of aldehydes in the presence of ketones and for the reduction of ketones in the presence of structurally different ketones and other functional groups.

C8H15ClO [+ H] -> [Cl +] C8H16O
Transformation of acid chlorides into the corresponding aldehydes without over-reduction to alcohols was effectively achieved by the reduction of acyltributylphosphonium ions, formed in-situ from the chlorides and tributylphosphine in CH3CN, with Zn-Cu co ple or Zn in the presence of CH3SO3H under an N-2 atmosphere.

C14H12OS [+ O] -> [S +] C14H12O2
A catalytic, high yielding transformation of thioketones to ketones at room temperature is described. is described.

C8H8 [+ H2O] -> C8H10O
Novel chiral bidentate N,N'- and N,P- donors and their rhodium complexes were synthesised and characterized. The reactions of ({Rh(COD)Cl}(2)) and (RhCl(PPh(3))(3)) with different prepared chiral ligands: (S)-1-L-2-t-butylaminocarbonylpyrrolidine (la, Ib) (S)-1-L-2-diphenylphosphinomethylpyrrolidine (2a, 2b), (S)-1-L-2-(1-naphthylaminocarbonyl)pyrrolidine (5a, 5b), (S)-1-L-2-(1-naphthylaminomethyl)pyrrolidine (7a, 7b) (a: L = t-butylaminocarbonyl, b: (3-trietoxysilylpropyl)aminocarbonyl) in the presence o a non-coordinating anion (PF6-) gave the cationic tetracoordinate (Rh(L(2))(ligand))(PF6) (L(2) = COD or PPH3). The structures of these complexes were elucidated by elemental analysis, IR spectroscopy and H-1, C-13 and P-31 NMR. measurements. The metal c mplexes with Ib, 2b, 5b and 7b, were anchored to silica and modified USY-zeolite and Rh-heterogenized complexes were obtained. A comparative study (homogeneous vs. supported) was made for the catalytic activity and selectivity in several organic reactions

C6H5NO3 [+ H2] -> [O2 +] C6H7NO
Treatment of a variety of nitroaromatic compounds with N,N-dimethyl- hydrazine in the presence of catalyc FeCl3 . 6H(2)O in methanol results in excellent yields of the corresponding anilines. This reduction system is compatible with a wide assortment of f nctional groups.

C17H19ClN2S [+ O] -> C17H19ClN2OS
The aerial oxidation of various phenothiazines to the corresponding sulfoxides is catalysed by nitric oxide and related nitrogen oxides. The reactive intermediate in the catalytic autoxidation is the phenothiazine cation radical which is subsequently tran formed to the sulfoxide by nitrate present in the reaction medium. These results are pertinent to any further discussion of the activity and/or metabolism of phenothiazine-based drugs.

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