Amino Acids. II. Synthesis of Cyclic Guanidino Acids¹

AMINO ACIDS: X. PREPARATION AND CHEMISTRY OF 2-(Ω-Carboxyalkylamino)-Dihydrothiazines, -TETRAHYDROPYRIMIDINES, AND -IMIDAZOLINES

“…The presence of the pentad (1) (11) (Ill) ( I Vl system -C=N-CH?-C=O is responsible for the mobility of the hydrogens a t Cz. Further proof of the presence of an active methylene group was obtained by condensiilg these bicyclic compounds (I, n = 2 and 3) with benzaldehydes to form the correspoilding 2-benzylidene derivatives (V).…”

“…The.bicyclic compounds 3-lteto-l,2,5,G-tetral~ydro-3(I-I)-imidazo(l,2-a)ii~1idazole'~ and 3-lteto-1,2, G,7-tetrahydro-3(I-I), 5(I-I) -i i d a z o ( l , -) p y r i m i d i n e k were previously described (1). I t has now been found that the original melting points given for these bicyclic compounds and their picrates are in error.…”

New data on the alkylation of cyclic thioureas with á-halocarboxylic acids and their esters. 2. Alkylation of tetrahydropyrimidine-2(1h)-thione and 5,5-dimethyltetrahydropyrimidine-2(1h)-thione

“…Tetrahydropyrimidine-2(1H)-thione (1) was prepared according to [8]; mp 209-210°C (mp 209°C [9]). 1 H NMR spectrum, δ, ppm: 7.78 (2H, s, NH 2 ); 3.13 (4H,m, 2H-4,6); 1.77 (2H, m,2H-5).…”

The unit-cell dimensions and space groups of 2-(benzylthio)imidazoline and 2-(benzylthio)tetrahydropyrimidine hydrochlorides

“…In the course of investigations on the structure of thioamides, cyclic thioureines and related compounds (Piazzesi, Bardi, Mammi & Walter, 1964;Mammi, D'Angeli & Bezzi, 1965;Del Pra, D'Angeli & Di Bello, 1966) the hydrochlorides of 2-(benzylthio)imidazoline (I) and of 2-(benzylthio)tetrahydropyrimidine (II) (McKay & Hatton, 1956) have been examined by X-rays.…”