A Novel and Direct Method for the Preparation of 4‐Amino‐1,1,3,3‐tetrasubstituted Guanidines and of [1,2,4]Triazolo‐Fused Heterocyclic Derivatives.

Abstract

Ring closure reactionsRing closure reactions O 0130 A Novel and Direct Method for the Preparation of 4-Amino-1,1,3,3-tetrasubstituted Guanidines and of [1,2,4]Triazolo-Fused Heterocyclic Derivatives. -The versatility of the chloroformamidinium salts (II) for the synthesis of guanidine derivatives (III) and of [1,2,4]triazolo-fused heterocycles like (V), (VII), and (IX) is demonstrated. -(ABDUL-GHANI, M.; KHATTAB, S. N.; EL-MASSRY, A. M.; EL-FAHAM*, A.; AMER, A.; Org. Prep. Proced. Int. 36 (2004) 2, 121-127; Dep. Chem., Fac. Sci., Beirut Arab Univ., Beirut, Lebanon; Eng.) -H. Haber 35-033

Chloroformamidinium salts: Efficient reagents for preparation of 2‐aminobenzoimidazole, 2‐aminobenzoxazole, and 2‐aminobenzothiazole derivatives

“…R f : 0.83 (CH 2 Cl 2 /MeOH 9:1); ir (potassium bromide): 3100-2900 (C-H), 1620 (C=N), 1540-1500 (C=C aromatic), 1480 (-CH 2 -), 1300 (C-N) cm -1 . 4-Benzyl-1-pyrrolidin-1-yl- [1,2,4]triazolo [4,3-a]quinoxaline (6b) [10].…”

“…UV/VIS (Ethanol): max =219 nm ( = 21050); max=260 nm ( =13410); max =327 nm ( =5290). UV/VIS (CH 3 CN): max =207 nm ( =23560); max = 258 nm ( =13020); max =327 nm ( =4970); ir (potassium bromide): 3100-2860 (C-H), 1620 (C=N), 1525-1500 (C=C aromatic), 1460 (-CH 2 -), 1300 (C-N) 40.24, 51.91, 116.00, 126.73, 126.77, 128.15, 128.40, 129.60, 129.75, 136.44, 136.70, 142.89, 154.50, 155.50 3-Pyrrolidin-1-yl- [1,2,4]triazolo [3,4-a]phthalazine (7a) [10].…”

“…119 ºC (dec). 88, 47.75, 119.27, 120.52, 121.49, 127.49, 130.83, 132.88, 137.20, 143.54, 146.45 3-Piperidin-1-yl- [1,2,4]triazolo [3,4-a]phthalazine (7b) [10].…”

“…In recent work [10] we reported the reaction of chloroformamidinium salts 1a and 1b with aryl hydrazine derivatives to give 4-amino-1,1,3,3-tetrasubstituted guanidines 2 (Figure 1), as well as reaction with heterocyclic hydrazino derivatives such as 3-benzyl-2-hydazinoquinoxaline 3, 1-hydrazinophthalazine hydrochloride 4, and 6-benzyl-5-hydrazino-2H- [1,2,4]triazin-3-one 5 to give [1,2,4]triazolo derivatives 6-8 respectively in high yields and purity, due to in situ heterocyclization and substitution of one of the dialkylamino groups (Scheme I) [11].…”

“…Chloroformamidinium salts (DmTCFH, 1c) and (DmPCFH, 1d) also, reacted with 3-benzyl-2-hydrazinoquinoxaline 3 and 1-hydrazinophthalazine hydrochloride 4 in the presence of triethyl amine as a base, to afford the [1,2,4]triazolo derivatives 6 and 7, respectively in good yield and purity (Scheme IV). These triazole derivatives have been prepared previously [10], and formed due to the strong tendency towards heterocyclization [11] and substitution of the diemthylamine group which acted as the better leaving group verified by their spectroscopic data, mass spectra, and elemental analysis.…”