3-Methyl-4-quinazolone

The quinazoline ring also gives some anomalous quatemization reactions, which presumably reflect the influence of the unusual 3,4-bond. 3-Methyl-4-quinazolone (71 Y = O) and, more... 

The methiodide of quinazoline (63) was studied by Gabriel and Colman and shown to possess structure 64. Gabriel s evidence has been checked by later workersand the substitution in the 3-position proved beyond all doubt, for example, by conversion via the pseudo base 65 into 3-methyl-4-quinazolone (66). It is significant... 

Synthesis from quinazoline precursors was achieved by carrying out a Vilsmeier-Haack reaction on 3-amino-2-methyl-4-quinazolone (96) to give the intermediate diformyl derivative 97 that cyclized to 3-formylpyra-zolo[5,l-b]-quinazolin-9-one (98) [73IJC532 84IJC(B)161]. 

Methyl isatogenate and 2-phenylisatogen react with tetracyanoethyl-ene, or trichloroacetonitrile, in boiling xylene to give quinazolones (154 R = C02Me, Ph).63,72 No reaction occurs with acetonitrile, and N-benzoylanthranilic acid is formed when 2-phenylisatogen is treated with potassium cyanide (see also Section III,A,1). No mechanism has been proposed for this unusual reaction. 

Two new quinazoline alkaloids of unusual structure were obtained from the seed husks of Zanthoxylum arborescens.12 Infrared, H n.m.r., and mass spectroscopy showed that the major alkaloid was a quinazolone containing a phenethyl substituent. The 13C n.m.r. spectrum indicated that an iV-methyl rather than an O- methyl group was present, but the spectroscopic studies did not distinguish between structures (19 R = H) and (20 R = H). The alkaloid was shown to be the iV-phenethyl derivative (20 R = H) by synthesis (Scheme 4), and a minor... 

SYNS MELSEDIN METHYLQULN AZOLONE HYDROCHLORIDE 2-METH X-3-TOLYLCHIN-AZOLON-4 HYDROCHLORIDE (GERMAN) 2-METHYL-3-o-TOL X-4(3H)-QUINAZOUNONE HYDROCHLORIDE 2-METH X-3-(o-TOL X)-4-QUINAZOLONE HYDROCHLORIDE MTQ HYDROCHLORIDE OPTIMIL PAREST SOMNAFAC TUAZOLE... 

Spiroquinazolines (114) can be obtained from hydrazides 104 and cyclohexanone (X = CH2) or l-methyl-4-piperidone (X = NMe).176 y-Ketocarbox-ylic acids as 2-acetylpropionic acid (115) form the condensed quinazolones 116 or 117, depending on the substitution of the ring and hydrazine nitrogens. With 2-acetylbenzoic acid (118), the analogous tetracyclic derivative 119 is obtained176,177 (Scheme 20). Half a mole of hydrazine hydrate with one mole... 

Etaqualone, 3-(2-Ethylphenyl)-2-methyl-4(3H)-quinazolinone 2-methyl -3 -(o-ethyIpheny])-4, -quinazolone,... 

Conformational studies on the pyrazino[2,1 - )]quinazolones (40), incorporating the cyclodipeptide Sar-Gly, have shown that the methyl derivative (R = Me) exists in the (40a) conformation, whereas the analogue with hydrogen (R = H) is conformationally flexible <74JCS(P1)2122,82AX(B)1654>. 

Methyprylon. Interestingly, the two piperidinediones viz., glutethimide and methyprylon and the quinazolone viz., methaqualone, are of vital importance within the context of non-barbiturate sedatives and hypnotics. However, glutethimide and methyl prylon possess a striking resem-blanee to barbiturates as given below ... 

The use of molybdenum compounds in organic synthesis has attracted greater attention. Thus, molybdenum hexacarbonyl has been used in various reactions, such as the preparation of disulfides from sulfonyl chlorides, the alkylation of aryl derivatives, and the synthesis of 4-quinazolones from amines Oxygen has been replaced by fluorine with molybdenum hexafluoride. Molybdenum pentachloride in combination with hydroperoxides has served as oxidant Chelates of MoOg " have been investigated as catalysts for oxidations with molecular oxygen 2,2-Dichloro-7-butyrolactones have been prepared from olefins and methyl trichloracetate with cyclopentadienylmolyb-denum tricarbonyl dimer as catalyst ... 

Methylene-2-quinazolones. Startg. m. warmed with coned. HCl, whereupon at 65° tert-hnty chloride starts to distil, and heated 1 hr. at 90° after the distillation 3,4-dihydro-3-methyl-4-methylene-2-quinazolone. Y 9S%. F. e. s. A. Brack, A. 730, 166 (1969). 

An ethanolic soln. of an/iy ro-5-hydroxy-3-hydroxymethyl-l-methylpyridazinium hydroxide irradiated at room temp, under Ng with the Pyrex-filtered light of a 100 w. high-pressure Hg-arc lamp -> 3-methyl-6-hydroxymethyl-4(3H)-pyrimi-dinone. Y 75%. F. e. s. Y. Maki et al., Tetrah. Let. 1974, 4107 4(3)-quinazolones from 4-hydroxycinnolinium betaines s. D. E. Ames, S. Chandrasekhar, and R. Simpson, Soc. Perkin I 1975, 2035. 

The use of methyl anthranilate (26) in the Niementowski reaction was reported by Meyer and Wagner in 1943. One of the factors limiting the usefulness of the Niementowski synthesis under conventional conditions is the propensity of anthranilic acid to undergo thermal decarboxylation at sustained heating of 150 °C or above. Methyl anthranilate, however, is stable at temperatures approaching its boiling point of 260 °C. Moreover, it was found to react with formamide at about 200 °C to form the expected 4-quinazolone product in 49% yield. Extension of this procedure to amides larger than acetamide, however, did not result in improved yields compared to the use of anthranilic acid. 

In 1900 Bogert and Gotthelf synthesized 2-methyl-4-quinazolone by heating anthranilic acid (1) and acetonitrile in a sealed tube at 200-210 °C for 6 h. They were able to confirm the identity of the product by comparison of the analytical data with the product produced by the original method published by Niementowski. 

Heating 3,4-diaminopyridine with chloroacetic add gives 6-aza-2-quinazolone (IX-217), However, if glycollic acid or acetic anhydride is used instead of chloroacetic acid, 2-hydroxymethylimidazo [4,5-c] pyridine and 2-methyl-imidazo[4,5-c] pyridine are obtained, respectively. ... 

Derivatives of 2-methyl-3-(o-tolyl)-4(3H)-quinazolone (Scheme 13.10) bearing new snbstitnents on the 2-methyl group have been synthesized. It was established that most substitutions at this position reduce or remove the CNS-depressant activity of methaqualone [48]. 

---