Reaction of Phosgene with the Tricycle Related to the Minor Base of Phenylalanine Transfer Ribonucleic Acids.

Abstract

1-Benzylwye (8) underwent electrophilic substitution at the 7-position in the presence of phosgene and pyridine in tetrahydrofuran (THF) to afford the 1,4-dihydropyridines (11, 10, and 14) together with the carboxylic acid 6 and its methyl ester 2 after short treatment of the reaction mixture with methanol and then with water. When triethylamine was used instead of pyridine, phosgene reacted with triethylamine rather than 8, producing (E)-3-(diethylamino)propenoyl chloride (17) and diethylcarbamoyl chloride (18).

Attempted reduction of 1,2,3-thiadiazole-4-carboxylates with samarium/iodine in methanol. Unexpected ring enlargement to 1,2,5-trithiepan-4,6-dicarboxylates

“…Compound 9 was identified by comparison of 1 H NMR data with those of the authentic specimen. 14 On similar treatment, 7b again produced 9 in comparable yield.…”

“…The residue was chromatographed on silica gel using hexane-ethyl acetate (10 : 1 v/v) to give 9 (13 mg, 31%). 14 Colourless oil. 1 H NMR: d 7.44 (d, J = 13 Hz, 1H, NCHCH), 4.57 (d, J = 13 Hz, 1H, CHCHCO 2 Me), 3.66 (s, 3H, CH 3 ), 3.19 (q, J = 7.2 Hz, 4H, 2 × CH 2 CH 3 ), 1.16 (dd, J = 7.2 Hz, 6H, 2 × CH 2 CH 3 ); MS (EI): m/z 157 (M + ).…”