Sarcosine decarboxylation

Fig. 2. Synthesis of uma2enil (18). The isonitrosoacetanihde is synthesized from 4-f1iioroani1ine. Cyclization using sulfuric acid is followed by oxidization using peracetic acid to the isatoic anhydride. Reaction of sarcosine in DMF and acetic acid leads to the benzodiazepine-2,5-dione. Deprotonation, phosphorylation, and subsequent reaction with diethyl malonate leads to the diester. After selective hydrolysis and decarboxylation the resulting monoester is nitrosated and catalyticaHy hydrogenated to the aminoester. Introduction of the final carbon atom is accompHshed by reaction of triethyl orthoformate to...

If secondary AAs are heated in the presence of aldehydes containing a proximate terminal double or triple bond and then condensed, decarboxylation and intramolecular cycloaddition tri-, tetra-, penta-, or hexa-cyclic cycloadducts with a condensed pyrrole ring are formed. An example is the reaction with sarcosine (Scheme 55) (88T4953). 

For the sake of brevity, this reaction was written in one step, whilst it probably proceeds through several stages, first forming a linear anhydride which then decarboxylates and finally cyclises. It seems significant that diketopiperazine is formed on reacting tertiary amines with sarcosine NCA1 and its yield may be as high as 35% [see ref. (3), p. 318]. It should be stressed, however, that this process involves an N-substituted NCA, whereas in the polymerisation of the non-N-sub-stituted NCA s no substantial amounts of diketopiperazines, if any,... 

Spirooxindoles, such as, for example ( )-coerulescine (101) have been prepared employing a sequence starting from 2-fluoronitrobenzene, which was initially subjected to treatment with the anion of dimethyl malonate, followed by decarboxylation and concomitant installation of the methylene group using formaldehyde in the presence of potassium carbonate to produce the intermediate 102 in good yield. This material readily underwent dipolar cycloaddition with the azomethine ylide generated from sarcosine and formaldehyde, followed by a reductive cyclization of adduct 103 to furnish the natural product 101 <02TL9175>. 

During investigations on the carbonyl-assisted decarboxylation of N-alkylated ot-amino acids, Rizzi found that azomethine ylide intermediates are involved in the decarboxylative condensation (70JOC2069). Heating sarcosine and benzophenone at 170°C (or benzaldehyde at 150-170°C) gave 3-methyl-2,2,5,5-tetraphenyloxazolidine, which corresponds to the cycloadduct of azomethine ylide 98 to the carbonyl compound. This sequence may involve the initial formation of iminium carboxylate betaines and subsequent decarboxylation to generate nonstabilized azomethine ylides [Eq. (15)]. This... 

During investigations on the carbonyl-assisted decarboxylation of N-alkylated a-amino acids, Rizzi found that azomethine ylide intermediates are involved in the decarboxylative condensation (70JOC2069). Heating sarcosine and benzophenone at 170°C (or benzaldehyde at 150-170°C) gave... 

Secondary and tertiary amines are formed from precursors other than amino acids. Dimethylamine results from degradation of choline (which is present in some phospholipids), some alkaloids (e.g. in beer it is produced from gramine (see 10-198) present in germinating barley grains and also in non-enzymatic browning reactions from methylamine and formaldehyde or by decarboxylation of sarcosine. Trimethylamine, together with dimethylamine, methylamine and ammonia, is an odorous compound of fish and other aquatic animals. It is formed by reduction of the sensory indifferent trimethylamine oxide (trimethylaminoxide, 8-143) in tissues post mortem. 

There are several examples in literature on cycloaddition of alkenes to azomethine ylides, generated in situ by decarboxylative condensation of isatins with an a-amino acid, sarcosine (MeNHCH2C02H), for architecture of pyrrolidine ring in spiro-pyrrolidine-oxindoles [55]. The cycloaddition of ylide 62 from N-methylisatin 58 and sarcosine to 3,4-diphenylcyclobutene-l,2-dione 63 proceeded smoothly to afford the product 64 (Scheme 20) [56]. 

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