Über Derivate von Thiazolcarbonsäuren

Synthesis and antiallergy activity of 5-oxo-5H-thiazolo[2,3-b]quinazolinecarboxylic acids

“…7-Methoxy-5-oxo-5JT-thiazolo [2,[3][4][5][6] ]quinazoline-2carboxylic Acid (5b). A suspension of 13.77 g (0.048 mol) of 4b and 52 mL (0.052 mol) of 1 N NaOH in 500 mL was stirred at room temperature for 2 h. The resultant suspension was concentrated in vacuo to remove the MeOH.…”

“…7-(Methylsulfinyl)-5-oxo-5if-thiazolo [2,[3][4][5][6]quinazoline-2-carboxylic Acid (5d). To 1.02 g (0.0035 mol) of 5c suspended in 25 mL of water was added 3.5 mL (0.0035 mol) of 1.0 N NaOH.…”

“…This oil was shaken vigorously with Et20 in which it appeared insoluble, and the resulting suspension filtered rapidly under vacuum. The Et20 filtrate was saved and stored overnight at -30 °C to yield as a precipitate 0.62 g of 4 (0.001 mol, 25%): fine, cream-white crystals; mp >300 °C (with decomposition); IR (Nujol) 1610 (biphenyl), intense bands 1310,1250 (alkyl ether), 1080,1060 (morpholinium ether), 830 (p-phenyl) cm"1; 1H NMR (CDC13) 7.61 (s, 8 H, aromatic), 4.35-3.85 (m, 4 H, methylene adjacent to morpholine oxygen), 3.62-3.35 (m, 8 H, ethoxy methylene and methylenes adjacent to bromine), 3.31-2.15 (overlapping signals, 12 H, methylenes adjacent to nitrogen), 1.23 (t, 6 H, ethoxy methyl). Anal.…”

“…The CH2C12 extract was dried over anhydrous MgS04, rotary evaporated to a pale yellow oil, and dissolved in Na-dried benzene. The addition of dry HC1 precipitated the hydrochloride salt of 5 (HC3-BrM-2HCl) (25 mg, 4.1 X 10'6 mol, 27%): IR (Nujol) 3500-3100 (associated hydroxy), 1670 (very weak, phenyl carbonyl), 1610 (biphenyl), 1070,1060 (mopholinium ether), 815 (p-phenyl) cm"1; NMR (Me2CO-d6) 7.9-7.78 (m, 8 H, aromatic), 4.36-3.8 (m, 4 H, methylene adjacent to morpholine oxygen), 3.76-3.5 (overlapping signals, 6 Phenacyl bromide (50 g, 0.185 mol) in 250 mL of EtOH was added with stirring to diethanolamine (31.5 g, 0.333 mol) dissolved in 50 mL of EtOH, and the resulting solution was refluxed for ~3 h. Following this, the acetal base 9 was obtained by a repeat of the extraction procedure for 2. Solution of 9 in ethanolic HC1 and addition of Et^O resulted in precipitation of the hydrochloride salt: yield 24 g (0.083 mol, 33%); mp 124-126 °C.…”

“…10-HC1 (0.35 g, 0.001 mol) was treated with 20 mL of H2S04 (1 M) in a procedure identical with that outlined for the preparation of HC3-BrM-2HCl. The yield of 11-HC1 was 0.16 g (5 X 10"4 mol, 50%): mp 127-128 °C; IR (Nujol) ¡w 3450 (associated hydroxy), 1680 (weak, phenyl carbonyl), 1070 (morpholinium ether), 760, 710 (monosubstituted phenyl) cm"1; NMR (CDC13) 7.7-7.45 (m, 2 H, aromatic), 7.43-7.20 (m, 3 H, aromatic), 4.4-3.45 (overlapping signals, 5 H, hydroxy, methylene adjacent to morpholine oxygen, methylene adjacent to bromine), 2.9-2.1 (overlapping signals, 6 H, methylenes adjacent to nitrogen).…”