Moses K. Kaloustian

One-pot synthesis of cyclic amidinium tetrafluoroborates and hexafluorophosphates; the simplest models of N5,N100methenyltetrahydrofolate coenzyme

Reaction of triethyl orthoesters with various N,N′-dialkyl-α,ω-alkanediamines in the presence of ammonium tetrafluoroborate or hexafluorophosphate, all in the same molar ratio, affords cyclic amidinium salts in excellent yields.

An Efficient Conversion of N-Alkyllactams to N-Alkylthiolactams

Abstract The lactam-to-thiolactam transformation is of considerable utility in the synthesis of natural products.3 We report on a two-step preparative route for the thionation of N-alkyllactams that is (i) superior to that effected by P4S10 4,5 or diethylthiocarbamoyl chloride6 (ii) safer and more efficient than the sulfhydrolysis of lactamium salts with H2S,3 and (iii) cleaner and thermally milder than that accomplished by the use of Lawessons reagent.7 The method is analogous to our lactone-to-thionolactone transformation8 and it consists of O-alkylation of the lactam (1) with R3O±BF4 (R=Me, Et),9 followed by treatment of the intermediate salt (2) with anhydrous NaSH10 in acetone at O°C. The following Table shows our results for the synthesis of thiolactams 9–13 when we apply our method (Method A) and those reported previously (Methods B-D).

A synthetic route to thionolactones

Abstract The treatment of O-alkyllactonium tetrafluoroborate salts with anh. NaSH in CH 3 CN at 0°C led to five-, six-, and seven-membered thionolactones (44– 90% yield).

Breakdown of cyclic dithiohemiorthoamide tetrahedral intermediates - RC(SR′)(NR″2)SH - at sub-zero temperatures 1,2☆☆☆

Abstract The uslfhydrolyses of thioimidate salts 2a – 2d , in the presence of anh. NASH in dry 2-butanone at −82°C, proceed by the preferential cleavage of the CN bond rather than the CS bond.

Photochemical transformations. Part XXXI. Photolysis of thiobenzoic acid O-esters. Part II. General methods for the preparation of thiobenzoic acid O-esters

Treatment of alkoxides with (thiobenzoylthio)acetic acid gives thiobenzoic acid O-esters in high yield. Similarly, the reaction of alkoxides with 2,4-dinitrophenyl dithiobenzoate (IX) gives the corresponding thiobenzoic acid O-ester. Imidate salts react with hydrogen sulphide in pyridine to give thioacid O-esters in good yields.