Deacylation and deformylation of pyrroles

Smith, Kevin M.; Miura, Michiko; Tabba, Hani D.

doi:10.1021/jo00172a067

Cited by 24 publications

(16 citation statements)

References 5 publications

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“…To prevent any Bioorganic & Medicinal Chemistry 4 possible side reactions, an attempt was made to protect the aldehyde group in 10 as an acetal. 10 As before, this failed to provide any of the desired product. There are reports in the literature of pyrrole-2-carboxaldehyde 4 reactions forming porphyrin-related structures, and this is likely to have been the outcome here.…”

Section: Resultsmentioning

confidence: 83%

“…Attempted protection of the aldehyde as an acetal failed to provide any protected product. 10,11 At this point a different route was required. The alcohol of 5 was protected with a TBDMS group to give silyl ether 6.…”

Section: Resultsmentioning

confidence: 99%

“…The oil was separated on silica using hexane : ethyl acetate (100 : 0 to 50 : 50) gradient eluent system. The desired product 3 (670 mg, 2.05 mmol, 49%) was isolated as colourless oil, which darkened and degraded over (10). Compound 3 degraded on standing, and could not be recovered by column chromatography.…”

Section: (S)-benzyl-2-((s)-2-((tert-butyldimethylsilyloxy)methyl)-pipmentioning

confidence: 99%

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Inhibition of prolyl oligopeptidase with a synthetic unnatural dipeptide

Racys¹,

Rea²,

Fülöp³

et al. 2010

Bioorganic & Medicinal Chemistry

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The synthesis of a new inhibitor of prolyl oligopeptidase, containing a piperidine ring, together with an X-ray structure of its complex with the enzyme, is described. This provides evidence that covalent inhibitors of POP do not have to be limited to structures containing 5-membered N-containing heterocyclic rings. inhibitor:Leave this area blank for abstract info. Abstract-A new inhibitor, containing a linked proline-piperidine structure, for the enzyme prolyl oligopeptidase (POP) has been synthesised and demonstrated to bind covalently with the enzyme at the active site. This provides evidence that covalent inhibitors of POP do not have to be limited to structures containing 5-membered N-containing heterocyclic rings.

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Section: Resultsmentioning

confidence: 83%

Section: Resultsmentioning

confidence: 99%

Section: (S)-benzyl-2-((s)-2-((tert-butyldimethylsilyloxy)methyl)-pipmentioning

confidence: 99%

See 1 more Smart Citation

Inhibition of prolyl oligopeptidase with a synthetic unnatural dipeptide

Racys¹,

Rea²,

Fülöp³

et al. 2010

Bioorganic & Medicinal Chemistry

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“…The method does not require the preparation of sodium benzoxide and instead uses catalytic sodium methoxide which is commercially available as a powder. Table 1 Comparison of traditional synthesis of 1 with synthesis using microwave energy De-acetylation The traditional manner to deacetylate benzyl 4-acetyl-3,5-dimethyl-2-carboxylate 3 (Path B, Scheme 1) involves heating the pyrrole in a mixture of ethylene glycol and toluene with a catalytic amount of para-toluene sulfonic acid [10] (Scheme 3). The reaction is typically heated to reflux overnight (depending on the scale it can require several days) followed by a methanol/water recrystallization.…”

Section: Trans-esterificationmentioning

confidence: 99%

“…Dibenzyl malonate, a precursor in the Knorr synthesis of 1 is around 70 times more expensive than diethyl malonate (a precursor in the Knorr synthesis of 2) and around 10 times more expensive than benzyl acetoacetate (a precursor in the Knorr synthesis of 3). Although highly successful, both the trans-esterification and the de-acetylation routes involve harsh conditions and often produce colored crude products [9,10]. Recrystallization of the crude materials gives clean products, but we wished to avoid using the harsh conditions that render this step essential.…”

Section: Introductionmentioning

confidence: 99%

Microwave‐accelerated synthesis of benzyl 3,5‐dimethyl‐pyrrole‐2‐carboxylate

Regourd

Comeau

Beshara

et al. 2006

Journal of Heterocyclic Chem

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m ic ro wa ve en er gyEt hylen e g lyco l, p -TS A m ic ro wa ve en er gyBenzyl 3,5-dimethyl-pyrrole-2-carboxylate, a very useful pyrrole in porphyrin and dipyrromethene synthesis, can be synthesized via the Knorr-type reaction, but in low yield. Alternative routes to benzyl 3,5-dimethyl-pyrrole-2-carboxylate have been developed involving the trans-esterification of ethyl 3,5-dimethyl-pyrrole-2-carboxylate and the de-acetylation of benzyl 4-acetyl-3,5-dimethyl-2-carboxylate, both precursors being easily obtained using the Knorr reaction. These traditional methods involve treatment of the known products with a strong basic solution or heating for extended periods which often lead to decomposition. The use of microwave energy to promote these two reactions proves to be an extremely efficient way to obtain benzyl 3,5-dimethyl-pyrrole-2-carboxylate quickly, in high yield, and in excellent purity with no need for recrystallization. Of particular note is the use of catalytic sodium methoxide in benzyl alcohol, rather than stoichiometric amounts of sodium benzoxide, to effect benzylation.

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Transformation of an Acid Dipyrromethane into its Formyl Dipyrromethane without Decarboxylation

Burns

Burden

1998

J. Porphyrins Phthalocyanines

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A method for the preparation of an α-formylated pyrrole or dipyrromethane which contains an electron-withdrawing β-acetyl is described. Formylation proceeds directly from the corresponding acid pyrrole or dipyrromethane without the need of the usual two-step acid decarboxylation/formylation procedure. The acid is first transformed into its acid chloride with oxalyl chloride, followed by reduction to the aldehyde with the mild reducing agent sodium triacetoxyborohydride, in a one-pot reaction. The non-basic acylating reagent PR 3 is necessary both for acyl chloride formation and for the reduction to succeed.

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Deacylation and deformylation of pyrroles

Cited by 24 publications

References 5 publications

Inhibition of prolyl oligopeptidase with a synthetic unnatural dipeptide

Inhibition of prolyl oligopeptidase with a synthetic unnatural dipeptide

Microwave‐accelerated synthesis of benzyl 3,5‐dimethyl‐pyrrole‐2‐carboxylate

Transformation of an Acid Dipyrromethane into its Formyl Dipyrromethane without Decarboxylation

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