Synthesis of enaminoamides of the 1,2,3,4-tetrahydroisoquinoline series

Shklyaev, V. S.; Aleksandrov, B. B.; Михайловский, А. Г.; Вахрин, М. И.

doi:10.1007/bf00487305

Cited by 20 publications

(15 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In contrast to that of the starting amide 1 the spectra of compounds 2a-d show doubling of the methyl and methylene group singlets. The proton of the ring NH group gives a signal in the region 9.0-10.5 ppm, this assignment being based on known data [2]. In the structures 3a-d two hydrazo forms are seen which most likely correspond to the s-cis-, trans isomers: A similar spectroscopic picture is seen for the tertiary amides.…”

supporting

confidence: 53%

See 1 more Smart Citation

Azocoupling reactions of enaminocarbonyl derivatives of 1,2,3,4-tetrahydroisoquinoline with diazonium salts

Polygalova

Михайловский

Вахрин

2006

Chem Heterocycl Compd

Self Cite

View full text Add to dashboard Cite

It has been shown that enamino amide and enamino ketone derivatives of 1,2,3,4-tetrahydroisoquinoline react with diazonium salts to form azo compounds. Depending on the enamine structure they can exist just as azo dyes or as azohydrazone tautomers.Up to this time the reactions of heterocyclic enamines with diazonium salts have been little studied. It has previously been shown [1] that the conjugation of an excess of a diazonium salt with 1,3,3-trimethyl-3,4-isoquinoline leads to the formation of formazans. Evidently the reaction products can also be an azo dye depending on the structural features of the enamine. The formation of dyes can also be expected from enaminocarbonyl compounds having only one hydrogen atom on the β-carbon atom of the enamine group in their structure (enamino amides and enamino ketones).The aim of this work is a study of the structure of the azocoupling reaction products and the dependence on the structure of the starting 1,2,3,4-tetrahydroisoquinoline enaminocarbonyl derivatives.This study has shown that the azocoupling of enamino amide 1 [2] with diazonium salts gives the azo dyes 2a-d which exist in solution as a tautomeric equilibrium with the hydrazo form (compounds 3a-d). The tertiary amide 4 [3] reacts similarly to give the azo dyes 5a,b which show a similar solution equilibrium (hydrazones 6a,b).It is known [4] that amides of type 7 exist in the imino form. However, in the azocoupling of the named amide with p-nitrophenyldiazonium chloride it reacts as an enamine to give the azo dye 8. It should be noted that the azo dye reaction product could only be separated for the p-nitro substituent. Attempts to use less active electrophiles as diazo component (such as the phenyl and p-tolyldiazonium chlorides) in the reaction did not give an azo conjugation product.Coupling of diazonium salts with the enamino ketone 9 [5] gave the azo dyes 10a,b and hydrazo formation was not seen in this case. The stability of the azo form can be explained by the greater electronacceptor effect of a ketone group when compared with an amide. In the case where the azo component is a tertiary enamino ketone the azo dyes 11a,b are also formed and exist in solution as a mixture of the two π-diastereomers (Z and E).

show abstract

supporting

confidence: 53%

“…This study has shown that the azocoupling of enamino amide 1 [2] with diazonium salts gives the azo dyes 2a-d which exist in solution as a tautomeric equilibrium with the hydrazo form (compounds 3a-d). The tertiary amide 4 [3] reacts similarly to give the azo dyes 5a,b which show a similar solution equilibrium (hydrazones 6a,b).…”

mentioning

confidence: 99%

Azocoupling reactions of enaminocarbonyl derivatives of 1,2,3,4-tetrahydroisoquinoline with diazonium salts

Polygalova

Михайловский

Вахрин

2006

Chem Heterocycl Compd

Self Cite

View full text Add to dashboard Cite

show abstract

“…The starting materials for the synthesis of compounds 2, 3 are described in [6,13,14], and of substances 5, 6 in [15]. Drotaverine base was isolated from tablets with a suitable expiry date, mp 58-60°C, its purity was checked by TLC.…”

Section: Methodsmentioning

confidence: 99%

Enamines of the 1,2,3,4-tetrahydroiso-quinoline series in the Chichibabin synthesis of pyrrolo[2,1-a]isoquinolines and in reaction with oxalyl chloride

Polygalova

Михайловский

Vikhareva

et al. 2007

Chem Heterocycl Compd

Self Cite

View full text Add to dashboard Cite

Pyrrolo[2,1-a]isoquinolines are used widely in organic synthesis, medicine, and other areas [1]. The classical method of design the pyrrolo[2,1-a]isoquinoline system is the interaction of 1-alkylisoquinolines with α-halo ketones (the Chichibabin reaction) [1,2]. It is known [3] that on cyclization with the formation of condensed systems a determining role is played by the radicals in position 3 of the isoquinoline ring. The aim of the present work is an investigation of the potentialities of this reaction in the presence of two methyl groups in position 3 and also of a different structure for the enamine fragment.The reaction of enamines of the 1,2,3,4-tetrahydroisoquinoline series with oxalyl chloride has also been widely investigated [1,4,5]. In the given examples, both bases, in the molecules of which the structure of the enamine is already fixed, and compounds in the imino form, enter into this reaction. The latter is characteristic for derivatives of 1-alkylisoquinoline [6,7], the alkyl residue in the structure of which, unlike carbonyl or just withdrawing groups, does not aid stabilization of the enamine form. Consequently our aim is the study of the conditions of carrying out and the structures of the products of the named reaction in the presence of an alkyl residue at position 1 of the isoquinoline ring.The investigations showed that the reaction of enamines 1a-c with p-bromophenacyl bromide proceeds readily on boiling in alcohol in the presence of Na 2 CO 3 and compounds 2a-c are formed. On using drotaverine (no-spa) base as the initial enamine the reaction product is compound 2d. Enamino amides and enamino esters of the benzo[f]isoquinoline series, analogous in structure to compounds 1a-c, form the corresponding tetracyclic derivatives 3a-c in this reaction. __________________________________________________________________________________________ Perm State Pharmaceutical Academy,

show abstract

“…Derivatives 5a,b [9], and 5d [10] were prepared according to reported procedures. A solution of p-benzoquinone (1.08 g, 10 mmol) in dry methylene chloride (20 ml) was added to a solution of corresponding starting enamine (10 ml) in dry methylene chloride (50 ml).…”

Section: Methodsmentioning

confidence: 99%