Niementowski

Friedlander synthesis, 2, 444 Benzacridinones, dihydro-von Niementowski synthesis, 2, 447 Benz[6]acridinones, tetrahydro-von Niementowski synthesis, 2, 447 Benzaldehyde... 

Dia2oaminoben2ene has also been prepared by the action of nitrous acid gas on aniline in alcohol by the action of silver nitrite on aniline hydrochloride and together with phenylurea by the action of nitrosophenylurea on aniline in methyl alcohol. Niementowski and Roszkowski have reported studies on the diazotization of aniline, aniline hydrochloride, and aniline sulfate with sodium nitrite and silver nitrite. The procedure described is adapted from that of Fischer. ... 

Niementowski lind Roszkowski, Z. physik. Chem. 22, 158 (1S97). 

The Niementowski reaction involves condensation of an o-aminobenzoic acid (13) with 2 resulting in a quinolinol (14). 

Microwave irradiation of a mixture of substituted anthranilic acid 224 with formamide (5 equiv) at 150 °C for 5 min gave quinazoUnones 225 in good yields (Scheme 82). This microwave version of the Niementowski reaction [ 143] showed significantly improved yields compared to the conventional reaction conditions [144]. 

Another multistep protocol that initially involves the formation of fused pyrimidines (quinazolines) has been described by Besson and coworkers in the context of synthesizing 8f-/-quinazolino[4,3-b]quinazolin-8-ones via double Niementowski condensation reactions (Scheme 6.250) [437]. In the first step of the sequence, an anthranilic acid was condensed with formamide (5.0 equivalents) under open-vessel microwave conditions (Niementowski condensation). Subsequent chlorination with excess POCl3, again under open-vessel conditions, produced the anticipated 4-chloro-quinazoline derivatives, which were subsequently condensed with anthranilic acids in acetic acid to produce the tetracyclic 8H-quinazolino[4,3-b]quinazolin-8-one target structures. The final condensation reactions were completed within 20 min under open-vessel reflux conditions (ca. 105 °C), but not surprisingly could also be performed within 10 min by sealed-vessel heating at 130 °C. 

Scheme 6.250 Formation of 8H-quinazolino[4,3-b]quinazolin-8-ones through double Niementowski condensation.

The same authors have described a related Niementowski condensation for the preparation of 3H-nitroquinazolin-4-ones. Subsequent manipulation of this structure led to 8H-thiazolo[5,4-/ quinazolin-9-ones through a series of open-vessel microwave-assisted transformations, as indicated in Scheme 6.251 [205, 438]. 

A more elaborate example is the Niementowski reaction to give access to quinazo-linones and quinolines [62], The determining step consists in the reaction of anthra-nilic acid with some amides or ketones (Eq. 11). 

The most important synthesis in this class is that of quinolines, due to Friedlander, with its major modifications by Pfitzinger and by von Niementowski. The Friedlander synthesis has been comprehensively reviewed (77HC(32-1)181, 820R(28)37, 80T2359), the last two reviews dealing only with the true Friedlander procedure. This is exemplified in equation (52), and the various possible modifications are indicated by the substituents. 

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