Formamide acetal

The Batcho-Leimgruber indole synthesis involves the condensation of o-nitrotoluene derivatives 1 with formamide acetals 2, followed by reduction of the trans-p-dimethylamino-2-nitrostyrene 3 which results to furnish indole derivatives represented by... 

Several types of substituted formamide acetals have been utilized in the Batcho-Leimgruber reaction, including N,N-dimethylformamide dimethyl and diethyl acetals, N-... 

Ag+acetate — Ag acetate+e, formamide, acetic acid 0.4266 73Nay... 

All reactions proceed in high yield and under mild conditions produce relatively pure products. The most effective 8-dimethyl ami no methylenating agents currently available are the formamide acetals,0 some of which are... 

PfirrwYYkT r.H.mm.i. mw aa. nu rn. —77.91% white powdr transition pt 160° (loss of w of hydration, Ref 5) and 225° decompn pt 290° (Ref 6). Sol in ethanol, dimethyl formamide, acet, tetrahydrofuran and dimethyl sulfoxide si sol in benz and w. According to Satriana (Ref 6) the dibasic salt is prepd in 92.5% yield by reacting Pb monoxide with /J-resorcylic acid in a 1 3 molar ratio in 50% ethanol at RT for five hours under a current of air. The prod is filtered off, washed with ice cold 50% ethanol and oven dried at 100° to constant wt... 

Acyl anions (RC(=0)M) are unstable, and quickly dimerize at temperatures >-100 °C (Section 5.4.7). These intermediates are best generated by reaction of organolithium compounds or cuprates with carbon monoxide at -110 °C and should be trapped immediately by an electrophile [344—347]. Metalated formic acid esters (R0C(=0)M) have been generated as intermediates by treatment of alcoholates with carbon monoxide, and can either be protonated to yield formic acid esters, or left to rearrange to carboxylates (R0C(=0)M —> RC02M) (Scheme 5.38) [348]. Related intermediates are presumably also formed by treatment of alcohols with formamide acetals (Scheme 5.38) [349]. More stable than acyl lithium compounds are acyl silanes or transition metal acyl complexes, which can also be used to perform nucleophilic acylations [350],... 

As can be seen in Table I, variation of the substituent has a profound effect on the rate of reaction of the o-nitrotoluene derivative with dimethyl-formamide acetals, but has little effect on the yields, which are often almost quantitative. As can be predicted, electron withdrawing groups accelerate the reaction. To shorten the somewhat lengthy reaction times which are often... 

Andrew D. Batcho and Willy Leimgruber 214 INDOLES FROM 2-METHYLNITROBENZENES BY CONDENSATION WITH FORMAMIDE ACETALS FOLLOWED BY REDUCTION 4-BENZYLOXYINDOLE... 

A total synthesis of ( + )-mitomycins via isomitomycin A is described (87JA7881), and from a mitomycin rearrangement albomitomycin A and isomitomycin A were formed from mitomycin A (87JA7224). Amidine derivatives were prepared from mitomycin C and formamide acetals. These, when treated with amines, afforded the corresponding 7-N-substituted mitosanes (87JOC5601). 

Cyclopropanation of 209 by a formamide acetal represents a cyclopropane synthesis from a dianion and a C(l)unit . 210and 211 were formed ina6 4ratio (equation 51). No rearrangement of 210 and 211 could be detected on standing at 70°C in CeDg. 

In addition to the construction of the amidine structure iV-alkylation reactions can occur,ring opening in the case of heterocyclic amines and formylation of acidic methylene or methyl groups. 76i,793 jjjg reaction of formamide with excess /V,N-dialkylformamide acetals deviates from this reaction pattern, here azavinylogous formamide acetals (358 Scheme 62) are formed. A, A -Dialkyl-iV -formylformamidines (359) can be prepared either by action of A, N-dialkylformamide acetals on bis(trimethylsilyl)formamide or by treatment of azavinylogous amide acetds (358) with trimethyl-chlorosilane. ... 

In a usually less favorable procedure formamide acetals (437 equation 204) are accessible from chloroform or trichloroacetic acid esters and mixtures of secondary amines and alkoxides - dichlorocar-bene is thought to be an intermediate. Chloromethoxycarbene, generated from the diazirine (438 equation 205) inserts into the NH bond of diethylamine to yield the amide acetal (439). The undissociated a,a-difluorotrialkylamines (440 Scheme 80) react with the alkali metal salts of diols to afford 1,3-dioxanes or l,3-dioxolMes7 - Noncyclic amide acetals can be prepared in the same manner. 

An important synthesis for formamide acetals with bulky alkoxy groups or with -aryl substituents starts from the corresponding formamidinium salts or from bis(didkylamino)acetonitriles the reaction with alcoholic alkoxides furnishes the amide acetals (449 Scheme 83).7 -32.35 ju tjjg reaction of the azavinylogous formamidinium salt (450) with methanolic methoxide a mixture of -dimethylform-amide dimethyl acetal and its azavinylogous derivative is produced. 

Transamination of amide acetals is possible and of synthetic value if high boiling, strongly nucleophilic secondary amines are to be introduced. Ketene 0,iV-acetals add alcohols to yield amide acetals (468 equation 216). From tetrakis(dimethylamino)ethylene and methanol a mixture of amide acetals, e.g. (469) and (470 equation 217), is formed. Azavinylogous formamide acetals (471 equation 218) are accessible by the action of formide acetals on tris(formylamino)methane or form-amide. ... 

Formamide acetals in synthesis of heterocycles 79T1675. Heteroannulation with O-aminoaldehydes 80T2359. 

Isothiouronium chlorides (317) undergo condensation reactions with formamidinium chloride (318a) or substituted formamide acetals (318b), and with acyl chlorides (319a) or anhydrides (319b) furnishing 2,5-disubstituted or 2,4,5-trisubstituted thiazoles in moderated yields (Scheme 79) <85S414>. 

The most important general methods for enaminone preparation are (i) direct condensations of ammonia or amines with 1,3-diketones or 3-ketoesters, (ii) nucleophilic reactions of lactams or related compounds with vinylogous acid chlorides, (iii) transformations catalyzed by organopalla-dium complexes, and (iv) the reactions of active methylene compounds with formamide acetals. This last method (iv) has been reviewed in detail... 

A review of the chemistry of formamide acetals with inter alia some carbohydrate and nucleoside examples has appeared. 

Formic acid—Formyl chloride—Formamide—Acetic acid— Kolbe s experiments, K kul s theory, etc.—Rohland s experiments capronic, caprylic and heptylic acids, unde-cylenic and oleic acids—Acetic acid, continued—Chlor-... 

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