Gabriel condensation

The first reported synthesis of an IF scaffold dates to 1884 when Gabriel condensed 2 equiv. phthalic anhydride (6) with ethyl acetoacetonate (7) to form carboxylic acid 8 and later ethyl ester 9 (Scheme 1) [16]. 

B. Gabriel Condensation and Ing-Manske Modification 13-S. Preparation of a, Diaminoadipic Add... 

For the sake of applicability, the preparation of a,(5-diaminoadipic acid using the Ing-Manske modification is given here, although the same reference indicates that, at least in this case, the Gabriel condensation and hydrolysis affords a higher yield. 

Gabriel condensation, 124-126 Ing-Manske modification, 124-126 Gattermann condensation, 50 Goldberg reaction, 93 Grignard coupling, 14-15,17 Grignatd method, 54-56 Grignard reaction, 31,50, 59,94,176,187, 246-248... 

In 1896, Gabriel and Freiherr von Hirsch (96) condensed CSj with what they believed to be 1-aminopropylene (2-methylaziridine) and obtained isomeric 4- and S-methyl-Z-mercaptothiazoline (63 and 64). 

Probably first obtained by Hantzsch and Arapides (105) by condensation of a,/3-dichlorether with barium thiocyanate, and identified by its pyridine-like odor, thiazole was first prepared in 1889 by G. Popp (104) with a yield of 10% by the reduction in boiling ethanol of thiazol-2-yldiazonium sulfate resulting from the diazotization of 2-aminothiazole. prepared the year before by Traumann (103). The unique cyclization reaction affording directly the thiazole molecule was described in 1914 by Gabriel and Bachstez (106). They applied the method of cyclization, developed by Gabriel (107, 108), to the diethylacetal of 2-formylamino-ethanal and obtained thiazole with a yield of 62% - Thiazole was also formed in the course of a study on the ease of decarboxylation of the three possible monocarboxylic acids derived from it (109). On the other... 

Since the structures of the Gabriel-Isay condensation products of 5,6-diaminopyrimidines with unsymmetrical 1,2-dicarbonyl or a-substituted monocarbonyl compounds are always ambiguous, the synthesis of 6- and 7-substituted pteridines by an unambiguous approach was and still is a necessity and an important challenge. 

Pteridine, 4-imino-1 -methyl-1,4-dihydro-basicity, 3, 270 Pteridine, 7-methoxy-synthesis, 3, 297 Pteridine, 2-methyl- H NMR, 3, 285 reactions, 3, 288 structure, 3, 266 Pteridine, 4-methyl-Gabriel s synthesis, 3, 309 H NMR, 3, 285 reactions, 3, 288 structure, 3, 266 Pteridine, 6-methyl-bromination, 3, 301 structure, 3, 266 synthesis, 3, 312 Pteridine, 7-methyl-aldol-type condensation, 3, 302 bromination, 3, 301 H NMR, 3, 285 structure, 3, 266 synthesis, 3, 312 Pteridine, 2-methylamino-solubility, 3, 271 Pteridine, 2-methyl-3,4-dihydro-striicture, 3, 279 Pteridine, 6-methyl-3,4-dihydro-structure, 3, 279... 

A wide variety of M W-assisted aldol [59, 60] and Knoevenagel condensation reactions have been accomplished using relatively benign reagents such as ammonium acetate [61], including the Gabriel synthesis of phthalides with potassium acetate [62],... 

In the first year of the 20th century, there was a new finding concerning the synthesis of pteridine, known as Gabriel-Coleman synthesis. In this method, pteridine derivatives are generally produced through the condensation of 2,3-diaminopyrimidine 55 with a-diketone (Eq. 5). One century has passed since the development of Gabriel-Coleman synthesis, however, modern synthetic procedures of tetrahydrobiopterin (43) conceptually depend on this synthe-... 

The application of Gabriel-Coleman synthesis to the synthesis of biopterin (30) is reliable, however, it has a serious problem in that the condensation of the pyrimidine precursor with asymmetrically substituted sugar derivatives is sometimes less regioselective or even nonregioselective. For example,... 

Synthesis from acylaminocarbonyl compounds and phosphorus pentasulfide and related condensations (Type C) Gabriel s synthesis... 

Non-functionalized A2-thiazolines (328) are obtained by the classical Gabriel s synthesis which condenses a thioamide (326) with 1,2-dibromoalkanes (327 Scheme 215) (1890CB157). When an N-arylthioamide is employed, the product (329) is a 3-arylthiazolinium salt. This constitutes the only route to these salts with an aryl group substituted on the nitrogen atom. 

Proof of the structure of the pyrazines was established in 1893 by Wolff (22), who converted tetramethylpyrazine to piperazine (8) by the series of reactions shown. The conversion of a-amino ketones to pyrazines requires the loss of hydrogen as well as the loss of water. Gabriel and Pinkus (23) obtained considerably higher yields when oxidizing agents were added to the reaction mixture after the condensation had been allowed to take place. Snape and Brooke (14) in 1897 established that amarone was identical with benzoinimide, ditolanazotide, tetraphenylazine, and tetraphenylpyrazine. 

Sato, M., Ebine, S., Akabori, S. Condensation of halobenzenes and haloferrocenes with phthalimide in the presence of copper(l) oxide a simplified Gabriel reaction. Synthesis 1981,472 73. 

Giustetto, Roberto, Llabres I Xamena Francesc X., Ricchiardi Gabriele, Bordiga Silvia, Damin Alessandro, Gobetto Roberto, and Chierotti Michele R. 2005. Maya blue a computational and spectroscopic study. Journal of Physical Chemistry. B, Condensed Matter, Materials, Surfaces, Interfaces, Biophysical Chemistry 109 19360-19368. 

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