Reactions sodamide

Sodamide. This substance is prepared by the reaction between gaseous ammonia and molten sodium ... 

The formation of ethyl acetoacetate is an example of a general reaction knowu as the acetoacetlc ester condensation in which an ester having hydrogen on the a-carbon atom condenses with a second molecule of the same ester or with another ester (which may or may not have hydrogen on the a-carbon atom) in the presence of a basic catalyst (sodium, sodium ethoxide, sodamide, sodium triphenylmethide) to form a p-keto-ester. The mechanism of the reaction may be illustrated by the condensation of ethyl acetate with another molecule of ethyl acetate by means of sodium ethoxide. ... 

The acetoacetic ester condensation (involving the acylation of an ester by an ester) is a special case of a more general reaction term the Claisen condensation. The latter is the condensation between a carboxylic ester and an ester (or ketone or nitrile) containing an a-hydrogen atom in the presence of a base (sodium, sodium alkoxide, sodamide, sodium triphenylmethide, etc.). If R—H is the compound containing the a- or active hydrogen atom, the Claisen condensation may be written ... 

Sodamide is first prepared in situ by the reaction of sodium with Uquid ammonia in the presence of a catalyst ... 

This reaction involves the condensation of an aldehyde or ketone with an a-halo ester in the presence of a basic condensing agent (sodium ethoxlde, sodamide, finely divided sodium or potassium iert.-butoxide) to give a glycldio (or ap-epoxy) ester. Thus acetophenone and ethyl chloroacetate yield phenyl-methylglycidic ester (I) ... 

Sodium forms unstable solutions in Hquid ammonia, where a slow reaction takes place to form sodamide and hydrogen, as foUows ... 

Phosphoms trichloride and pentachloride form sodium chloride and sodium phosphide, respectively, in the presence of sodium. Phosphoms oxychloride, POCl, when heated with sodium, explodes. Carbon disulfide reacts violendy, forming sodium sulfide. Sodium amide (sodamide), NaNH2, is formed by the reaction of ammonia gas with Hquid sodium. SoHd sodium reacts only superficially with Hquid sulfur dioxide but molten sodium and gaseous... 

The greatest improvement in the manufacture of indigotin came when sodamide was used with alkali in the conversion of phenylglycine to indoxyl (125). Not only was the fusion temperature lowered from about 300°C to 200°C, but also the reaction was made practically anhydrous by the sodamide... 

Methylpyrazine reacts with sodamide in liquid ammonia to generate the anion, which may be alkylated to give higher alkylpyrazines (Scheme 10) (61JOC3379). The alkylpyrazines have found extensive use as fiavouring and aroma agents (see Section 2.14.4). Condensation reactions with esters, aldehydes and ketones are common, e.g. methyl benzoate yields phenacylpyrazine in 95% yield, and reactions of this type are summarized in Scheme 11. 

In contrast to electrophilic reagents, the highly -tt-deficient character of the pteridine nucleus is responsible for its vulnerability towards nucleophilic attack by a wide variety of reagents. The direct nucleophilic substitution of pteridine itself in a Chichibabin-type reaction with sodamide in diethylaniline, however, was unsuccessful (51JCS474). Pteridin-6-one, on the other hand, yielded pteridine-6,7-dione under the same conditions, via a still unknown reaction mechanism. 

A MIXTURE of 120 g. (3 moles) of sodamide (Note i) and 200 cc. of purified mineral oil (Note 2) is ground together in a mortar until the amide is finely pulverized (Note 3). This suspension is transferred to a 2-I. round-bottom, three-necked flask fitted with a reflux condenser holding a calcium chloride tube, a 500-cc. separatory funnel, and an efficient mechanical stirrer through a mercury seal. The mortar and pestle are rinsed with an additional 250 cc. of the oil which is then added to the reaction flask. This is heated in an oil bath maintained at 160-165, the stirrer is started and 203 g. (i mole) of cyclohexylbromopropene (p. 20) is dropped in during one and one-half hours. Ammonia is evolved and this is allowed to pass through the condenser and is collected in water. 

The thenyl cyanides are of great importance for the preparation of thiophene derivatives. Because of the acidifying effects of both the thienyl and of the cyano groups, carbanions are easily obtained through the reaction with sodamide or sodium ethoxide, which can be alkylated with halides, carbethoxylated with ethyl carbonate, or acylated by Claisen condensation with ethyl... 

Ammonolysis of 2-chlorobenzothiazole in liquid ammonia was studied by Lemons et al. and found to be approximately first-order with respect to this substrate at the fairly high concentrations used. The actual nucleophilic reagent was, as expected, the neutral species NH3, and reaction via the amide ion NH2 arising from the autoprotolysis equilibrium [Eq. (5)] was excluded on the grounds that addition of ammonium chloride did not depress the reaction rate. In accordance with this interpretation and in connection with the existence of aromatic substitutions other than normal it is of interest that 2-chlorobenzothiazole was found to react difiFerently with sodamide, although the products were unidentified in this case. 

Studies of the reaction of 3-deuteropyridine and 3-picoline with sodamide has shown that this type of amination does not proceed through a pyridyne intermediate as had been postulated recently. 

Only rarely is the amino group itself anionized during nucleophilic substitution one instance is the reaction of sodamide with 2-aminopyridine to yield 2,6-dianJnopyridine (cf. structure 74 on p. 185). 

To a slurry of sodamide in 200 cc of toluene representing 6.7 g of sodium was added at 30° to 40°C, 32.3 g (0.31 mol) of 2-aminopyridine. The mixture was heated to reflux temperature and was refluxed for VA hours. To the resulting mixture was added over a period of approximately one hour a solution of 32 g of freshly distilled N,N-dimethyl-i3-chloroethylamine in 40 to 50 cc of dry toluene. The reaction mixture was then haated for 2 hours at reflux temperature. Thereafter, 200 cc of water was added and the toluene layer was separated and washed with water. The toluene was stripped from the mixture by distillation and the residue was distilled under reduced pressure. The distillate was refractionated and the portion distilled at 93° to 103°C/1 mm was recovered. Yield of N-(2-pvridvl)-N, N -dlmethyl-ethvlenediamine, 60%. 

Preparation of 1,3-Diphenyl-2,2-Dimethylpropanone-1 Sodamide was prepared from 12.5 grams of sodium added in small portions to 600 cc of liquid ammonia with 1 gram of hydrous ferric chloride as catalyst. The ammonia was replaced by 200 cc of dry toluene and without delay a solution of 74 grams of isobutyrophenone and 76.5 grams of benzyl bromide in 200 cc of benzene was slowly added with stirring. The reaction mixture was heated on a boiling water bath for 48 hours. Water was then added, the organic layer separated and the product isolated by distillation. The 1,3-diphenyl-2,2-dimethylpropanone-1 boiled from 142°-143°C at a pressure of 3 mm, t ° 1.5652. 

A solution of 3-dimethylsulfamoylphenthiazine (5 g) in anhydrous xylene (100 cc) is heated under reflux for 1 hour with sodamide (0.67 g). 3-(4-methyl-1-piperazinyl)-1 heated under reflux for 5 hours. After treatment of the reaction products, a crude oily base (2.5 g) is obtained after treatment. By the addition of a solution of fumaric acid in ethanol to an ethanolic solution of the base, 3-dimethylsulfamoyl-10-(3-4 -methyl-1 -piperazinylpropyD-phenthiazine diacid fumarate (2.6 g) is obtained, melting point 182°C. The base recrystallized from ethyl acetate melts at about 140°C. 

Only on reaction of this salt with sodamide in liquid ammonia is the expected diphosphazene obtained ... 

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