EXPANDING THE SYNTHETIC POTENTIAL OF THE IMINE VARIANT OF THE PUDOVIK REACTION: NEW TYPES OF ORGANIC PHOSPHORUS COMPOUNDS AND NEW REACTIONS
Rubrics: 1. CHEMISTRY
Authors:
1.
KNITU; KNRTU,
2.
KNITU
3.
KNITU
4.
Kazan National Research Technological University
5.
KNITU; KNRTU,
6.
Kazan National Research Technological University
Kazan, Russian Federation
Kazan, Russian Federation
7.
Kazan National Research Technological University
8.
Kazan National Research Technological University
9.
KNITU
Type:
Article
Pages:
from 5
to 30
Status:
In work
Language:
Russian
Keywords:
PUDOVIK REACTION, REACTION SYNTHETIC POTENTIAL, DIALKYL PHOSPHITES, O.O- DIALKYLDITHIOPHOSPHORIC ACIDS, N-ALKYL-2-HAL-AND 2,2-DIHALALDIMINES, ADDITION PRODUCT, AZIRIDINIUM SALT, IMINE NITROGEN ATOM PROTONATION, INTERMEDIATE IMINIUM SALT, NUCLEOPHILIC SUBSTITUTION, REDUCTION ON THE C-HLG BOND
Abstract (English):
The study of the interaction of dialkylphosphites (DAPh), dialkyldithiophosphoric and diphenyl- and diethyldithiophosphinic acids with halogen- and dihalogen-substituted aldimines in the aldehyde fragment has significantly expanded the synthetic potential of the imine version of the Pudovik reaction: new types of phosphorus compounds have been constructed, and reactions previously undescribed in the literature have been discovered. In the products of the addition of DAPh to N-alkyl-2-chloroaldimines, isomerization of the 2-chloroalkyl radical of P(IV) into 1-chloroalkyl radical through an intermediate aziridinium salt is carried out. The latter is converted to phosphorus-containing aziridine and alkyl-2-(dialkoxyphosphoryl-1,1-dimethyl-2-chloroethyl)ammonium chloride, which is transformed to betaine - alkyl(2-methoxyphosphonato-1,1-dialkyl-2-chloroethyl)ammonium at methoxyl groups at P(IV). N-alkyl-2-bromaldimine reacts with DAPh with the release of methyl bromide to form a compound of quite a different structure: 2-methoxyphosphonatoaziridinium. The above-mentioned new types of organic phosphorus compounds were synthesized by the discovered new reactions of DAPh with N-alkyl-2-halogenaldimines. In the reaction of N-alkyl-2-chlor- and bromaldimines with O,O-dialkyldithiophosphoric and diphenyl- and diethyldithiophosphinic acids, the imine nitrogen atom is first reversibly protonated to form the initial intermediate iminium salt. The further transformation of this salt depends on the nature of the halogen, on the dithioacid structure and the ratio of the reagents. Three new reactions of phosphorus dithioacids with N-alkyl-2-hal- and 2,2-dihalaldimines were discovered: 1) with N-alkyl-2-chloraldimines in a ratio 1: 1, where the initial iminium salt is transformed into a new iminium salt - N-alkyl-2-(dialkoxythiophosphorylthio)aldiminium chloride, via the nucleophilic substitution of the chlorine atom by O,O-dialkylthiophosphorylthio group in a labile addition product. When the initial ratio is 1:2, a new reaction route is implemented in parallel - the reduction of the initially formed iminium salt on the C-Hlg bond (C-Cl → C-H). In the reaction of 2-chloraldimines with diphenyl- and diethyldithiophosphinic acids, which are weaker than dithiophosphoric acids, both routes are realized: nucleophilic substitution and reduction. The contribution of each route depends on the acid strength and the ratio of reactants. In the case of diphenyldithiophosphinic acid, at an acid: imine ratio of 1:3, substitution prevails; 2) with N-alkyl-2-bromaldimines in ratios 1: 1 and 2: 1, where a dithioacid participates in the reduction of the primary iminium salt cation on the C-Br bond (C-Br→C-H).
The study of the interaction of dialkylphosphites (DAPh), dialkyldithiophosphoric and diphenyl- and diethyldithiophosphinic acids with halogen- and dihalogen-substituted aldimines in the aldehyde fragment has significantly expanded the synthetic potential of the imine version of the Pudovik reaction: new types of phosphorus compounds have been constructed, and reactions previously undescribed in the literature have been discovered. In the products of the addition of DAPh to N-alkyl-2-chloroaldimines, isomerization of the 2-chloroalkyl radical of P(IV) into 1-chloroalkyl radical through an intermediate aziridinium salt is carried out. The latter is converted to phosphorus-containing aziridine and alkyl-2-(dialkoxyphosphoryl-1,1-dimethyl-2-chloroethyl)ammonium chloride, which is transformed to betaine - alkyl(2-methoxyphosphonato-1,1-dialkyl-2-chloroethyl)ammonium at methoxyl groups at P(IV). N-alkyl-2-bromaldimine reacts with DAPh with the release of methyl bromide to form a compound of quite a different structure: 2-methoxyphosphonatoaziridinium. The above-mentioned new types of organic phosphorus compounds were synthesized by the discovered new reactions of DAPh with N-alkyl-2-halogenaldimines. In the reaction of N-alkyl-2-chlor- and bromaldimines with O,O-dialkyldithiophosphoric and diphenyl- and diethyldithiophosphinic acids, the imine nitrogen atom is first reversibly protonated to form the initial intermediate iminium salt. The further transformation of this salt depends on the nature of the halogen, on the dithioacid structure and the ratio of the reagents. Three new reactions of phosphorus dithioacids with N-alkyl-2-hal- and 2,2-dihalaldimines were discovered: 1) with N-alkyl-2-chloraldimines in a ratio 1: 1, where the initial iminium salt is transformed into a new iminium salt - N-alkyl-2-(dialkoxythiophosphorylthio)aldiminium chloride, via the nucleophilic substitution of the chlorine atom by O,O-dialkylthiophosphorylthio group in a labile addition product. When the initial ratio is 1:2, a new reaction route is implemented in parallel - the reduction of the initially formed iminium salt on the C-Hlg bond (C-Cl → C-H). In the reaction of 2-chloraldimines with diphenyl- and diethyldithiophosphinic acids, which are weaker than dithiophosphoric acids, both routes are realized: nucleophilic substitution and reduction. The contribution of each route depends on the acid strength and the ratio of reactants. In the case of diphenyldithiophosphinic acid, at an acid: imine ratio of 1:3, substitution prevails; 2) with N-alkyl-2-bromaldimines in ratios 1: 1 and 2: 1, where a dithioacid participates in the reduction of the primary iminium salt cation on the C-Br bond (C-Br→C-H).
Keywords:
PUDOVIK REACTION, REACTION SYNTHETIC POTENTIAL, DIALKYL PHOSPHITES, O.O- DIALKYLDITHIOPHOSPHORIC ACIDS, N-ALKYL-2-HAL-AND 2,2-DIHALALDIMINES, ADDITION PRODUCT, AZIRIDINIUM SALT, IMINE NITROGEN ATOM PROTONATION, INTERMEDIATE IMINIUM SALT, NUCLEOPHILIC SUBSTITUTION, REDUCTION ON THE C-HLG BOND
PUDOVIK REACTION, REACTION SYNTHETIC POTENTIAL, DIALKYL PHOSPHITES, O.O- DIALKYLDITHIOPHOSPHORIC ACIDS, N-ALKYL-2-HAL-AND 2,2-DIHALALDIMINES, ADDITION PRODUCT, AZIRIDINIUM SALT, IMINE NITROGEN ATOM PROTONATION, INTERMEDIATE IMINIUM SALT, NUCLEOPHILIC SUBSTITUTION, REDUCTION ON THE C-HLG BOND
