Aminoacetal

Arenaphthenequinone has been prepared from acenaplithene by oxidation with chromic acid,1 2 3 with calcium permanganate,4 with air in the presence of catalysts in various solvents,5 6 7 and by the formation of an oxime with amyl nitrite followed by hydrolysis.8 

To a solution of 197 g. (1 mole) of bromoacetal1 in 250 ml. of absolute alcohol, cooled in a hydrogenation bomb of about 1.1-1. capacity to the temperature of a Dry Ice-acetone bath, is added approximately 300 g. (about 18 moles) of liquid ammonia (Note 1). The bomb is closed, connected with a pressure gauge, and heated at 120-130° with shaking for 12 hours. The pressure rises to about 2300 pounds. 

After the bomb has cooled, the ammonia is allowed to escape (Note 2) and the solution is poured out. The bomb is rinsed with 

Some of the reaction mixture may be carried from the bomb by the escaping ammonia. If the ammonia is allowed to escape through a tube leading into a beaker or flask, this material can be collected. 

An appreciable amount of a slimy solid collects on the walls of the bomb. It appears to consist of ammonium bromide together with a small amount of iron salts dissolved from the walls of the bomb by the action of the ammonia. The amount of product recovered by careful working of this material is less than 2 g. 

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The preparation of 2-phenylthiazole from thiobenzamidoacetal (203) (readily prepared from aminoacetal) has also been reported (Scheme 107) (440). Compound 203 loses 1 mole of ethanol under mild dehydrating conditions to give 5-ethoxy-2-phenyl-A-2-thiazoline (204). This then loses a second mole of ethanol under more vigorous conditions to give 2-phenylthiazole (205). 

A variation involves the reaction of benzylamines with glyoxal hemiacetal (168). Cyclization of the intermediate (35) with sulfuric acid produces the same isoquinoline as that obtained from the Schiff base derived from an aromatic aldehyde and aminoacetal. This method has proved especially useful for the synthesis of 1-substituted isoquinolines. 

Cellulose chloroacetates (30) and aminoacetates (30,31), acetate sorbates (32), and acetate maleates (33) have been prepared but are not commercially important. These esters are made from hydrolyzed cellulose acetate with the appropriate anhydride or acid chloride in pyridine. 

Isequinoline synthesis Irom aromatic aldehydes and an aminoacetal (Pomeranz-Frttsch) or from phenethylamines and glyonal acetal (Schlitter-Muller). 

This was confirmed by an independent analytical method by Spath and Boschan, and by a synthesis of pellotine by Spath and Becke, starting from the benzyl ether of 2-hydroxy-3 4-dimethoxyacetophenone, which was converted by aminoacetal into the Schiff s base (V). This, on treatment with sulphuric acid (73 per cent.), followed by warm water, gave 8-hydroxy-6 7-dimethoxy-l-methyh 5oquinoline (VI), of which the methiodide, m.p. 188-189-5°, on reduction furnishes pellotine (IV). From dZ-pellotine so formed Spath and Kesztler, by a special process of fractionation, isolated 1-pellotine having — 15-2° (CHCI3), for which... 

The Pomeranz-Fritsch reaction involves the preparation of isoquinolines 4 via the acid-mediated cyclisation of the appropriate aminoacetal intermediate 3. The best yields are usually obtained when the benzaldehyde portion 1 has electron-donating substituents in the 3- or 3,4- positions relative to the aldehyde. 

Attempts to prepare isoindolenine (4) by pyrolytie or acid-eatalyzed elimination from the aminoacetal (36). proved fruitless, the only... 

Xmino-benzol, n. aminobenzene, aniline, -essig-siure,/. aminoacetic acid, glycine, -kohlen-saure, /. amidocarbonic acid, carbamic acid, sfiure, /. amino acid, -saurerest, m. amino acid residue, -verbindung, /. amino compound. -zucker, m. amino sugar. 

The amidines 10, prepared by condensation of the corresponding imidates with aminoacetal-dehyde dimethyl acetal, undergo cyclization with a variety of acids to l//-3-benzazcpin-2-amines 11 45 Method A has proved to be successful on an industrial scale. 

A further variant of Method B is the acylation of a 2-aminobenzophenone with a protected a-amino acid chloride, followed by conversion of the product 11 into the 2-(aminoacet-amido)benzophenone 12 by reaction with hydrobromic acid in acetic acid.196... 

Die Reduktionen von Thioharnstoff-Derivaten mit Hydriden verlauft analog den Harn-stoffen. So erhalt man z. B. aus Tetramethyl-thioharnstoff mit Lithiumalanat nach Hydrolyse des Aminoacetals Dimethylamin (73% d.Th.)1 ... 

Cyclohexanedione (316) and ethyl 2-amidino-2-aminoacetate (317) (as hydrochloride) gave ethyl 3-amino-5,6,7,8-tetrahydro-2-quinoxalinecarboxy-late (318) (HjO-EtOH, AcONa, 10°C, 5 h %). ... 

Palladium-catalysed asymmetrie allylations of various carbonyl compounds have been studied by Hiroi et al. using various types of chiral sulfonamides derived from a-amino acids. In particular, the chiral bidentate phosphinyl sulfonamide derived from (5)-proline and depicted in Scheme 1.63 was employed in the presence of palladium to eatalyse the allylation of methyl aminoacetate diphenyl ketimine with allyl aeetate, leading to the eorresponding (7 )-product with a moderate enantioseleetivity of 62% ee. This ligand was also applied to the allylation of a series of other nueleophiles, as shown in Seheme 1.63, providing the eorresponding allylated produets in moderate enantioseleetivities. 

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