Reaction Of Thioesters Research Articles

Hydrophobic Effect and Substrate Specificity in Reaction of Thioester and Amine in Water

Abstract The extent of hydrophobic effect in amidation reaction of alkyl thioester with alkylamine in water was studied. The yield of the products was primarily dependent on the alkyl group of amine. For example, the reaction of S-dodecyl dodecanethioate with dodecylamine proceeded in good yield, while the reaction did not occur with cyclohexylamine, piperidine, and dipropylamine. The effect of chain length of n-alkylamine was studied to suggest the presence of hydrophobic effect. The yield of amide also depended on the alkyl group of the thioester secondarily, but the effect was smaller than amine.

Straightforward Synthesis of gem‐Phosphonate‐Phosphate Containing Compounds via One‐Pot Reaction of Thioesters with Diethyl Phosphite.

A convenient straightforward, three step, one-pot reaction of diethyl phosphite with thioesters in the presence of catalytic amounts of potassium tert-butoxide in toluene or DMF as solvent provided various phosphonate-phosphate containing compounds in excellent yields.

The Reaction of Thioesters with Nitriles. A New Synthetic Approach to the Preparation of Substituted 4‐Alkylthio‐ and 4‐Arylthiopyrimidine Derivatives.

AbstractFor Abstract see ChemInform Abstract in Full Text.

The reaction of thioesters with nitriles. A new synthetic approach to the preparation of substituted 4-alkylthio- and 4-arylthiopyrimidine derivatives

S-Alkyl and S-aryl thioesters react with nitriles in the presence of triflic anhydride to form substituted 4-alkylthio- and 4-arylthiopyrimidines. However, when methyl thiocyanate is used as nitrile, dithioimidocarbonates are formed. A mechanism to explain these differences is postulated.

A New Simple Method for the Synthesis of Thiophene Derivatives — Generation of Thiocarbonyl Ylides form S-a-(Dimethylphenylsilyl)benzyl Acylates and Their Cycloaddition with Acetylenic Dipolarophiles —

The cycloaddition of S-α-(dimethylphenylsilyl)benzyl acylates (1) with acetylenic dipolarophiles via 1,4-silatropy proceeded readily to afford thiophene derivatives. The reaction of thioesters (1) with 1-diethylamino-1-propyne (A), an electron-rich acetylenic dipolarophile, gave 5-aryl-3-diethylamino-4-methyl-2-phenylthiophenes (3) and 4-aryl-2-diethylamino-3-methyl-5-phenylthiophenes (4). When dimethyl acetylenedicarboxylate (DMAD), an electron-deficient alkyne, was used, the reaction of thioesters (1) afforded thiophene derivatives (4) exclusively.

Putative Diels-Alder-Catalyzed Cyclization during the Biosynthesis of Lovastatin.

A Diels-Alder cyclization proposed to occur during polyketide synthase assembly of the bicyclic core of lovastatin (1) (mevinolin) by Aspergillus terreus MF 4845 was examined via the synthesis of the N-acetylcysteamine (NAC) thioester of [2,11-(13)C(2)]-(E,E,E)-(R)-6-methyldodecatri-2,8,10-enoate (5a). In vitro Diels-Alder cyclization of the corresponding unlabeled NAC ester 5b, ethyl ester 18b, and acid 20b yielded two analogous diastereomers in each case, under either thermal or Lewis acid-catalyzed conditions. The reaction of thioester 5 proceeds readily at 22 degrees C in aqueous media. For 18b, one product is trans-fused ethyl (1R,2R,4aS, 6R,8aR)-1,2,4a,5,6,7,8,8a-octahydro-2,6-dimethylnaphthalene-1-carboxylate (30) (endo product), and the other is cis-fused ethyl (1R,2S,4aR,6R,8aR)-1,2,4a,5,6,7,8,8a-octahydro-2,6-dimethylnaphthalene-1-carboxylate (31) (exo product). Isomer 21 with stereochemistry analogous to 4a,5-dihydromonacolin L (2), a precursor of 1, was made by transformation of a tricyclic lactone, (1S,2S,4aR,6S,8S,8aS)-1-(ethoxycarbonyl)-1,2,4a,5,6,7,8,8a-octahydro-2-methyl-6,8-naphthalenecarbolactone (22) using reduction and Barton deoxygenation. Comparison of 21 with 30 and 31 confirmed the structural assignments and showed that the nonenzymatic 4 + 2 cyclizations of 5, 18, and 20 proceed via chairlike exo and endo transition states with the methyl substituent pseudoequatorial. The proposed biosynthetic Diels-Alder leading to lovastatin (1) would require an endo conformation with the methyl substituent pseudoaxial. Intact incorporation of the labeled hexaketide triene 5a into 1 was not achieved because of rapid degradation by A. terreus cells.

Reactions of thioesters of trivalent phosphorus acids with complex alkali-metal hydrides

1. Thioesters of phosphinous, phosphonous, and diaminophosphorous acids react with lithium aluminum hydride to form the corresponding primary and secondary phosphines or diamides of hypophosphorous acid. 2. The use of crown ethers as phase-transfer catalysts in reduction reactions of thioesters of pIII acids makes it possible to increase the rate of the process and raise the yield of the final products.

Reactions of Thioesters and Thiolactones with Cyclopentadienylmetal Dicarbonyl Dimers

Reactions of Thioesters and Thiolactones with Cyclopentadienylmetal Dicarbonyl Dimers

Reaction of thioesters and thiolactones with cyclopentadienylmetal dicarbonyl dimers

Preparation des complexes LM 2 (CO) 4 (C 5 H 4 R) avec L=thioester ou thiolactone. Structure cristalline de [(C 5 H 5 ) 2 Mo 2 (CO) 4 (SC 4 H 6 0)]: groupe quadratique P4 2 bc avec a=19,872 et c=9,643 A, Z=8