Abstract: Processes for preparing isometrically pure 3-methylthiophene-2-carboxaldehyde, an intermediate for synthesis of anthelmintic agents, by reaction of mercaptoacetaldehyde or the dimer, or a polymer thereof, or a dialkylacetal thereof in the presence of a base with (1) methyl vinyl ketone or an alpha- or beta- oxidized derivative of methyl vinyl ketone to form a 3-oxobutylmercaptoacetaldehyde or dialkyl acetal thereof, or an alpha- or beta-substituted derivative thereof which is then converted to 3-methylthiophene-2-carboxaldehyde via appropriate steps including, if necessary, treatment with acid, followed, if necessary, by enamine catalyzed cyclization and, in the case of using methyl vinyl ketone as reactant, a dehydrogenation step; or (2) 3-butyn-2-one to produce a mixture of isomeric 3-oxobut-1-enylmercaptoacetaldehyde or dialkyl acetals thereof which is cyclized to 3-methylthiophene-2-carboxaldehyde.

Abstract: Processes for preparing isomerically pure 3-methylthiophene-2-carboxaldehyde, an intermediate for synthesis of anthelmintic agents, by reaction of mercaptoacetaldehyde or the dimer, or a polymer thereof, or a dialkylacetal thereof in the presence of a base with (1) methyl vinyl ketone or an alpha- or beta-oxidized derivative of methyl vinyl ketone to form a 3-oxobutylmercaptoacetaldehyde or dialkyl acetal thereof, or an alpha- or beta-substituted derivative thereof which is then converted to 3-methylthiophene-2-carboxaldehyde via appropriate steps including, if necessary, treatment with acid, followed, if necessary, by enamine catalyzed cyclization and, in the case of using methyl vinyl ketone as reactant, a dehydrogenation step; or (2) 3-butyn-2-one to produce a mixture of isomeric 3-oxobut-1-enylmercaptoacetaldehyde or dialkyl acetals thereof which is cyclized to 3-methylthiophene-2-carboxaldehyde.

Abstract: 5,6-Anhydro-L-ascorbic acid, 5,6-anhydro-D-erythorbic acid and salts thereof are disclosed. Such compounds are useful intermediates in the preparation of 6-deoxy-6-substituted-L-ascorbic acid and 6-deoxy-6-substituted-D-erythorbic acid, which are useful as antioxidants. Novel 6-deoxy-6-substituted-L-ascorbic and -D-erythorbic acid derivatives are also disclosed.

Abstract: 5-Keto-L-ascorbic acid-5,5-dimethyl ketal, alkali metal and alkaline earth metal salts thereof; process for the preparation thereof; its use as an antioxidant and intermediate for production of 5-keto-L-ascorbic acid and L-ascorbic acid. 5-keto-L-ascorbic acid and its 5,5-dimethyl ketal exhibit antiscorbutic activity.

Abstract: The novel stereoselective and regioselective alkali metal borohydride reduction of 2,5-diketogluconic acid, alkyl esters or salts thereof to form 2-ketogulonic acid together with lesser amounts of 2-ketogluconic acid is disclosed. The 2-ketogulonic acid is readily converted to ascorbic acid.

Abstract: 1-Aryloxy-2-(S)-hydroxy-3-(triarylphosphonio)-propane salts and alkali metal ylids thereof are novel intermediates useful in the direct synthesis of 15-(R)-hydroxy-16-aryloxy-prostaglandins.

Abstract: 5-Keto-L-ascorbic acid-5,5-dimethyl ketal, alkali metal and alkaline earth metal salts thereof; process for the preparation thereof; its use as an antioxidant and intermediate for production of 5-keto-L-ascorbic acid and L-ascorbic acid. 5-Keto-L-ascorbic acid and its 5,5-dimethyl ketal exhibit antiscorbutic activity.

Abstract: The novel stereoselective and regioselective alkali metal borohydride reduction of 2,5-diketogluconic acid, alkyl esters or salts thereof to form 2-ketogluconic acid together with lesser amounts of 2-ketogluconic acid is disclosed. The 2-ketogluconic acid is readily converted to ascorbic acid.

Abstract: 2,5-Diketogluconic acid, alkyl esters or salts thereof, are reduced by an amine-borane to 2-ketogulonic acid, an intermediate for the preparation of ascorbic acid.

Abstract: The novel stereoselective and regioselective alkali metal borohydride reduction of 2,5-diketogluconic acid, alkyl esters or salts thereof to form 2-ketogulonic acid together with lesser amounts of 2-ketogluconic acid is disclosed. The 2-ketogulonic acid is readily converted to ascorbic acid.