Quinazolones structure

The lack of structural specificity among sedative-hypnotic drugs has been alluded to before. It is perhaps not too surprising that quinazolones, too, show this activity. The prototype, methaqualone (149), is obtained in a single step from the condensation of the"anthranilamide, 148, with o-toluidine.(The reaction may well involve first formation of the bisamide cycli-zation will then give the quinazolone ring system.) Condensation... 

A series of piperazine-based antagonists was disclosed as potential obesity agents [77]. Compound 30 shows an hH3R K of 11 nM. Quinazolone 31 was highlighted, and may be of further interest as the specific synthesis and a crystal structure was disclosed [78]. 

In the case of a [l,2,3]triazolol,5- ]quinazolone derivative (closely related to 489) a direct one-step amination has been reported where the cyclic amide moiety is replaced by an amino substituted structural unit <2006OL2425>. 

Coupling 1-aminoanthraquinone onto pyrazolo-(5,lb)-quinazolone with the general structure... 

P.O.67 is a member of the pyrazolo-quinazolone pigment series. Its constitution is listed in the Colour Index under Constitution No. 12915. Coupling component is the heterocycle shown on p. 503. The diazonium component is 2-nitro-4-chloroani-line. Coupling affords the pigment, which was found to exhibit the hydrazone structure ... 

The particularly good activity against protein kinases of a-aminoquinazoline derivatives is borne out by their activity against both in vitro and in vivo models of human tumors. The examples that follow are but two of a number of compounds from this structural class that have emerged from the focus that has been devoted to this stmctural class. Nitration of the benzoate (78-1) with nitric acid affords the nitro derivative. Hydrogenation converts this to the anthrandate (78-2). In one of the standard conditions for forming quinazolones, that intermediate is then treated with ammonium formate to yield the heterocycle (78-3). Reaction of this last product with phosphorus oxychloride leads to the corresponding enol chloride (78-4). Condensation of this last intermediate with meta-iodoanUine (78-5) leads to displacement of chlorine and the consequent formation of the aminoquinazoline... 

The quinazolones methaqualone (129 R = Me) and mecloqualone (129 R = Cl) are anticonvulsants, but little structural variation can be made without loss of activity. The benzodiazepines which were first introduced as antianxiety drugs have proved useful as anticonvulsants, particularly diazepam (135) and nitrazepam (136). 

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... 

The structures of these alkaloids have recently been fully elucidated they have been shown to be 3-substituted quinazolones. 

Carboxylic acid chlorides add in a like manner to carbodiimides to form the corresponding 1 1 adducts, which have a chloroformamidine structure. For example, acetyl chloride was added to carbodiimides, and the structure of the labile 1 1 adducts (XXVII) was established by subsequent reactions with anthranilamide, leading to 4-quinazolones XXVIII... 

Vincent, M., J. Maillard, and M. Benard Structure and Properties of Alkyl Iodides of Alkyldihydro-4-quinazolones. Bull. Soc. Chim. Fr. 1963, 119. 

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... 

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