Synthesis of pyrimido[4′,5′:2,3][1,4]thiazepino[7,6-b]quinolines, derivatives of a novel ring system

Abstract

Synthesis of pyrimido[4′,5′:2,3][1,4]thiazepino [7,6b]quinolines, derivatives of a novel ring systemAbstract: Several derivatives of the novel pyrimido[4′,5′:2,3] [1,4]thiazepino[7,6-b]quinoline ring system have been synthesized through cyclocondensation of 5-amino-6-methylpyrimidine-4-thiols 5a,b and 2-chloroquinoline-3-carbaldehydes 6a-c in the presence of K 2 CO 3 in DMF.

Synthesis of New Pyrimido[5′,4′:5,6][1,4]thiazino[2,3‐b]quinoxaline Derivatives in One Step

“…The 13 C NMR spectrum of ( 3a ) also contains the distinguished signals of all of the carbon atoms. The IR spectrum did not show the NH 2 vibrational absorption bands at ν 3336 and 3248 cm −1 of the precursor , but an absorption band at ν 3239 cm −1 demonstrated the existence of the NH group in the product ( 3a ) and the IR spectrum showed the stretching vibrational bands of pyrrolidine and pyrimidine moieties. The mass spectrum of ( 3a ) also showed the molecular ion peak at m/z 336 (M + ) corresponding to the molecular formula of C 17 H 16 N 6 S. In continuation, the N ‐alkylation of compounds ( 3a–d ) with alkyl halides in KOH/DMF at 90°C gave the desired new derivatives of products ( 4a–g ) quantitatively (Scheme ).…”

“…Based on the mentioned facts and also in continuation of our previous studies in the synthesis of new heterocyclic compounds , the present study reports the synthesis of new derivatives of pyrimido[5′,4′:5,6][1,4]thiazino[2,3‐ b ]quinoxaline through the one‐pot heterocyclization of the appropriate 5‐amino6‐methylpyrimidine‐4‐thiols and 2,3‐dichloroquinoxaline. N ‐alkylation of the synthesized compounds with several alkyl halides also gave the desired new derivatives of N ‐alkylated pyrimido[5′,4′:5,6][1,4]thiazino[2,3‐ b ]quinoxalines ( 4a–h ).…”

“…Our previous published studies on the synthesis and using of 5‐amino6‐methylpyrimidine‐4‐thiols ( 1 ) in heterocyclization reactions prompted us to explore another aspects of treatment with the 2,3‐dichloroquinoxaline ( 2 ) thereby leading to the corresponding fused pyrimido[5′,4′:5,6] [1,4] thiazino[2,3‐ b ]quinoxaline ( 3a–d ) derivatives in the presence of K 2 CO 3 in dimethylformamide (DMF) under reflux. The heterocyclization occurred in one step and any intermediate was not isolated.…”

Synthesis of New Derivatives of 4‐(4,7,7‐Trimethyl‐7,8‐dihydro‐6H‐benzo[b]pyrimido[5,4‐e][1,4]thiazin‐2‐yl)morpholine

“…Our previous published study on the synthesis and using of 5-amino-6-methyl-2-morpholinopyrimidine-4-thiol (1) [26] in a typical heterocyclization reaction prompted us to explore another aspects of treatment with the synthesized 2-bromo-5,5-dimethylcyclohexane-1,3-dione (2) [27] through which obtained the corresponding fused 4,7,7-trimethyl-2-morpholino-7,8-dihydro-5H-benzo[b]pyrimido [5,4-e] [1,4] thiazin-9(6H)-one (3) in the presence of Et 3 N at room temperature (Scheme 1).…”

Synthesis of [1,2,4]Triazolo[3,4-b]Pteridines as a Novel Class of Heterocyclic Compounds

“…[8][9][10][11][12][13] Encouraged by these reports and in continuation of our interest in the synthesis of a variety of heterocyclic systems as biologically active compounds, [14][15][16][17] we describe here a facile synthesis and structural elucidation of some new [1,2,4]triazolo [3,4-b] pteridine derivatives as a novel heterocyclic system.…”