Synthese der p-Cumaroylspermidine

The Synthesis of p-Cumaroylspermidines The synthesis of three mono[(E)-3-(4-hydroxyphenyl)prop-2-enoyl]spermidines, 10, 20 , and 28 , three bis[(E)-3-(4-hydroxyphenyl)prop-2-enoyl]spermidines, 6, 16 , and 25 , and one tris[(E)-3-(4-hydroxyphenyl)prop-2-enoyl]-spermidine is described.     

Electrospray-Ionization Mass Spectrometry. Part III. Acid-Catalyzed Isomerization of N,N′-Bis[(E)-3-(4-hydroxyphenyl)prop-2-enoyl]spermidines by the Zip Reaction

The electrospray tandem mass spectra (ESI-MS/MS) of the three N,N′-bis[(E)-3-(4-hydroxyphenyl)prop-2-enoyl]spermidines 1–3 displayed the same fragment-ion signals. These isomers could not be differentiated by ESI-MS/MS, since their fragmentation patterns are similar. (E,E)-N-(3-[¹⁵N]Aminopropyl)-3,3′-bis(4- hydroxyphenyl)-N,N′-(butane-1,4-diyl)bis[prop-2-enamide] ([¹⁵N(1)])-( 1 ) was synthesized in order to get further information about the fragmentation mechanisms. The comparison of the ESI-MS/MS of 1 and [¹⁵N(1)]- 1 revealed a transamidation, the Zip reaction, under mass-spectral conditions of the [ 1 + H]⁺ ions. Because of this reaction, the three isomers 1–3 could not be distinguished.     

Electrospray-Ionization Mass Spectrometry. Part 2. Neighboring-Group Participation in the Mass-Spectral Decomposition of 4-Hydroxycinnamoyl-spermidines

The three mono substituted N-[(E)-3-(4-hydroxyphenyl)prop-2-enoyl]spermidines 1–3 have been studied by positive-ion electrospray-ionization tandem mass spectrometry (ESI-MS/MS). Because of the neighboring-group participation, the MS/MS of [ 1 + H]⁺ and [ 2 + H]⁺ are essentially similar, while compound 3 can be easily distinguished from 1 and 2 because of the characteristic ions at m/z 218. However, with the source collision-induced dissociation (source-CID) MS/MS technique, the compounds 1 and 2 can be unambiguously distinguished by the signal of the pyrrolidinium ion (m/z 72) from their daughter ion (m/z 275). The source-CID MS/MS of the labeled compound N-(4-aminobutyl)-N-(3-aminopropyl)-N-[3-(4- hydroxyphenyl)prop-2-en[¹⁵N]amide] ([¹⁵N(4)]- 2 ) provide more information on the decomposition mechanisms and proved the occurrence of a partial transamidation reaction 2→1 during the measurement.     

Allgemeiner Zugang zu Polyaminen mit Ethan-1,2-diamin-Einheiten: Synthese von nicht natürlich vorkommenden homologen und isomeren N1,4-Di(4-cumaroyl)sperminen

█tl="American"█The synthesis of the three N,N′-di(4-coumaroyl)tetramines, i.e., of (E,E)-N-{3-[(2-aminoethyl)amino]propyl}-3,3′-bis(4-hydroxyphenyl)-N,N′-(ethane-1,2-diyl)bis[prop-2-enamide] ( 1a ), (E,E)-N-{4-[(2-aminoethyl)amino]butyl}-3,3′-bis(4-hydroxyphenyl)-N,N′-(ethane-1,2-diyl)bis[prop-2-enamide] ( 1b ), and (E,E)-N-{6-[(2-aminoethyl)amino]hexyl}-3,3′-bis(4-hydroxyphenyl)-N,N′-(ethane-1,2-diyl)bis[prop-2-enamide] ( 1c ), is described. It proceeds through stepwise construction of the symmetric polyamine backbone including protection and deprotection steps of the amino functions. Their behavior on TLC in comparison with that of 1,4-di(4-coumaroyl)spermine (=(E,E)-N-{4-[(3-aminopropyl)amino]butyl}-3,3′-bis(4-hydroxyphenyl)-N,N′-(propane-1,3-diyl)bis[prop-2-enamide]; 2 ) is discussed.     

On-Line Coupling of High-Performance Liquid Chromatography to Atmospheric Pressure Chemical Ionization Mass Spectrometry (HPLC/APCI-MS and MS/MS). The Pollen Analysis of Hippeastrum x hortorum (Amaryllidaceae)

A H₂O/MeOH extract of the pollen of Hippeastrum x hortorum (Amaryllidaceae) was analyzed. A mixture of different compounds (at the most 84) was found, namely the geometrically ((E,E), (E,Z), (Z,E), and (Z,Z) and structurally isomeric N,N′-dicoumaroyl (=N,N′-bis[3-(4-hydroxyphenyl)prop-2-enoyl]), N,N′-diferuloyl (=N,N′-bis[3-(4-hydroxy-3-methoxyphenyl)prop-2-enoyl]), N,N′-disinapoyl (=N,N′-bis[3-(4-hydroxy-3,5-dimethoxyphenyl)prop-2-enoyl]), N-coumaroyl-N′-feruloyl, and N-feruloyl-N′-sinapoyl derivatives of spermidine (=4-azaoctane-1,8-diamine=N-(3-aminopropyl)butane-1,4-diamine). Their structures were proven by using on-line-coupled high-performance liquid chromatography and atmospheric-pressure chemical-ionization mass spectrometry (HPLC-UV(DAD)/APCI-MS and MS/MS), UV-induced (E)⇌(Z) photoisomerization, and catalytic hydrogenation, as well by comparing their spectra and chromatographic behavior with those of synthetic standards. According to the physicochemical properties of these natural compounds, a proposed biological function is discussed.     

Reactions of Elemental Phosphorus and Phosphine with Electrophiles in Superbasic Systems: XV. Phosphorylation of Allyl Halides with Elemental Phosphorus

Elemental phosphorus (red or white) reacts with allyl chloride and allyl bromide in a two-phase system aqueous KOH-organic solvent to form tertiary symmetrical and mixed phosphine oxides among which tris(prop-2-enyl)-, bis(prop-2-enyl)[(E)-prop-1-enyl]-, bis(prop-2-enyl)[(Z)-prop-1-enyl]-, (prop-2-enyl)[(E)-prop-1-enyl][(Z)-prop-1-enyl]-, bis[(E)-prop-1-enyl](prop-2-enyl)-, bis[(Z)-prop-1-enyl](prop-2-enyl)-, tris-[(E)-prop-1-enyl]-, and bis[(E)-prop-1-enyl][(Z)-prop-1-enyl]phosphine oxides were identified. The conditions (room temperature, 60% aqueous KOH-dioxane) allowing preparation from white phosphorus and allyl bromide of tris(prop-2-enyl)- and bis(prop-2-enyl)[(E)-prop-1-enyl]phosphine oxides as major products in the total yield of up to 96% were found.     

Reduction of (<Emphasis Type="Italic">E</Emphasis>)-3-aryl-2-(thiazol-2-yl)acrylonitriles with lithium aluminum hydride

Reduction of (E)-3-aryl-2-(4-arylthiazol-2-yl)acrylonitriles with lithium aluminum hydride in dry ether afforded (Z)-1-amino-3-aryl-2-(thiazol-2-yl)prop-1-ene derivatives in 15 to 40% yields. The structure of (Z)-1-amino-3-(2-chlorophenyl)-2-[4-(4-methylphenyl)thiazol-2-yl]prop-1-ene was confirmed by X-ray diffraction analysis. Dedicated to Academician N. K. Kochetkov on the occasion of his 90th birthday. __________ Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 1301–1303, May, 2005.     

Synthesis of new functionally substituted hetarylcarbamates from methyl {4-[(2<Emphasis Type="Italic">E</Emphasis>)-3-(4-methoxyphenyl)-prop-2-enoyl]phenyl}carbamate

Three-component condensation of methyl {4-[(2E)-3-(4-methoxyphenyl)prop-2-enoyl]phenyl}- carbamate with ninhydrin and L-proline in methanol–water (10: 1) afforded methyl {4-[1,3-dioxo-1′- (4-methoxyphenyl)-1,1′,2′,3,5′,6′,7′,7a′-octahydrospiro[indene-2,3′-pyrrolizin]-2′-ylcarbonyl]phenyl}carbamate. Heating of methyl {4-[(2E)-3-(4-methoxyphenyl)prop-2-enoyl]phenyl}carbamate with isatin and benzylamine in methanol gave methyl {4-[4′-(4-methoxyphenyl)-2-oxo-5′-phenyl-1,2-dihydrospiro[indole-3,2′-pyrrolidin]-3′-ylcarbonyl]phenyl}carbamate. The condensation of methyl {4-[(2E)-3-(4-methoxyphenyl)prop-2- enoyl]phenyl}carbamate with sarcosine and 11H-indeno[1,2-b]quinoxalin-11-one generated in situ from ninhydrin and o-phenylenediamine in boiling ethanol led to the formation of methyl {4-[4′-(4-methoxyphenyl)-1′-methyl-11,11a-dihydro-5aH-spiro[benzo[b]phenazine-6,2′-pyrrolidin]-3′-ylcarbonyl]phenyl}carbamate.     

Synthesis of (E)- and (Z)-3(5)-(2-hydroxyphenyl)-4-styrylpyrazoles

Abstract  

An efficient synthesis method for the preparation of a series of new (Z)- and (E)-3(5)-(2-hydroxyphenyl)-4-styrylpyrazoles was developed. The reaction of (Z)- and (E)-3-styrylchromones with hydrazine hydrate afforded the corresponding (Z)- and (E)-3(5)-(2-hydroxyphenyl)-4-styrylpyrazoles, except for nitro derivatives, where both (Z)- and (E)-4′-nitro-3-styrylchromones afforded (E)-3(5)-(2-hydroxyphenyl)-4-(4-nitrostyryl)pyrazoles. The reaction mechanism for these transformations is discussed and the stereochemistries of all products were established by NMR experiments.     

Synthesis of (<Emphasis Type="Italic">E</Emphasis>)- and (<Emphasis Type="Italic">Z</Emphasis>)-3(5)-(2-hydroxyphenyl)-4-styrylpyrazoles

Abstract  An efficient synthesis method for the preparation of a series of new (Z)- and (E)-3(5)-(2-hydroxyphenyl)-4-styrylpyrazoles was developed. The reaction of (Z)- and (E)-3-styrylchromones with hydrazine hydrate afforded the corresponding (Z)- and (E)-3(5)-(2-hydroxyphenyl)-4-styrylpyrazoles, except for nitro derivatives, where both (Z)- and (E)-4′-nitro-3-styrylchromones afforded (E)-3(5)-(2-hydroxyphenyl)-4-(4-nitrostyryl)pyrazoles. The reaction mechanism for these transformations is discussed and the stereochemistries of all products were established by NMR experiments. Graphical abstract        

Raspailynes,Novel Long-Chain Acetylenic Enol Ethers of Glycerol from the Marine Sponges Raspailia pumila and Raspailia ramosa

The sponges Raspailia pumila and ramosa (Demospongiae, Tetractinomorpha, Axinellida) from the North-East Atlantic are shown to contain a series of novel long-chain enol ethers of glycerol where the enol ether C?C bond is conjugated, in sequence, to both an acetylenic and an olefinic bond. Polar extracts give raspailynes hydroxylated at their (1Z5Z)-1,5-alkadien-3-ynyl chain, like raspailyne Al ( = (+)-(S)-3-[((1Z,5Z)-16-hydroxy-hexadeca-1,5-dien-3-ynyl)oxy]-1,2-propanediol; (+ 2 ) and isoraspailyne A ( = (+)-3-[((1Z,5Z)-17-hydroxyocta-deca-1,5-dien-3-ynyl)oxy]-1,2-[propanediol; (+)- 3 ). Less polar extracts give 3 different types of raspailynes not hydroxylated at the chain. Raspailynes of the first type have either the (1Z,5Z)-configuration in a linear chain such as raspailyne B2 (( = (?)-(s)-3-[((1Z,5Z)-trideca-1,5-dien-3-ynyl)oxy]-1,2-propanediol; (?)-4), raspailyne Bl ( = (?)-3-[((1Z,5Z)-tetradeca-1,5-dien-3-ynyl)oxy]-1,2-propanediol;(?)- 5 ), and raspailyne B ( = 3-[((1Z,5Z)-pentadeca-1,5-dien-3-ynyl)oxy]-1,2-propanediol; 6 ) or the (1Z,5Z)-pentadeca-1,5-dien-3-ynyl)oxy]-1,2-propanediol; 6 )or the (1Z,5Z)-configuration in a chain ending with an isopropyl group, like isoraspailyne Bl ( = 3-[((1Z,5Z)-12-methyltrideca-1,5-dien-3-ynyl)oxy]-1,2-propanediol; 7 ) and isoraspailyne B ( = 3-[((1Z,5Z)-13-methyltetradeca-1,5-dien-3-ynyl)oxy]-1,2-propanediol; 8 ). Raspailynes of the second type have the (1Z,5E)-configuration, like isoraspailyne Bla ( =3-[((1Z,5E)-tetradeca-1,5-dien-3-ynyl)oxy]-1,2-propanediol; 9 ) and isoraspailyne Ba ( = 3-[((1Z,5E)-13-methyltetradeca-1,5-dien-3-ynyl)oxy]-1,2-propanediol; 10 ). Raspailynes of the third type have the (1E,5Z)-configuration, like isoraspailyne Blb ( = 3-[((1E,5Z)-tetradeca-1,5-dien-3-ynyl)oxy]-1,2,-propanediol; 11 ). The (S)-configuration for (+)- 1 ,((+)- 2 , and (?)- 4 is derived from chemical correlations.     

Microwave assisted synthesis of substituted (<Emphasis Type="Italic">Z</Emphasis>)-2-{[1-phenyl-3-(thiophen-2-yl)-1<Emphasis Type="Italic">H</Emphasis>-pyrazol- 4-yl]methylene}benzofuran-3(2<Emphasis Type="Italic">H</Emphasis>)-ones and their antimicrobial activity

Aurones, pyrazole and thiophene scaffolds are known for their potential antimicrobial activity. Herein, we have synthesized hybrid compounds containing three substituted (Z)-2-{[1-phenyl-3-(thiophen-2-yl)- 1H-pyrazol-4-yl]methylene}benzofuran-3(2H)-ones that had been produced from substituted (E)-1-(2-hydroxyphenyl)- 3-[1-phenyl-3-(thiophen-2-yl)-1H-pyrazol-4-yl]prop-2-en-1-ones in high yields. All synthesized compounds were tested in vitro for their antimicrobial activity. Several of those demonstrated promising activity against some fungal and bacterial strains.     

Hepatoprotective phenylethanoid glycosides from Cirsium setosum

Two new phenylethanoid glycosides, namely β-D-glucopyranoside, 1″-O-(7S)-7-(3-methoxyl-4-hydroxyphenyl)-7-methoxyethyl-3″-α-L-rhamnopyranosyl-4″-[(8E)-7-(3-methoxyl-4-hydroxyphenyl)-8-propenoate] (1) and β-D-glucopyranoside, 1″-O-(7S)-7-(3-methoxyl-4-hydroxyphenyl)-7-methoxyethyl-3″-α-L-rhamnopyranosyl-4″-[(8E)-7-(4-hydroxyphenyl)-8-propenoate] (2), together with six phenylethanoid glycosides were isolated from Cirsium setosum. Their structures were elucidated by their spectroscopic data and references. Compounds 2, 4, 5, 7 and 8 (10 μM) exhibited moderate hepatoprotective activities. Compounds (3–8) were obtained from this plant for the first time.     

Formal synthesis of strobilurins A and X

Known synthetic precursors of strobilurins A and X, i.e., methyl (3Z,5E)-6-aryl-3-methylhexa-3,5-dienoates (aryl is phenyl, 4-methoxyphenyl), were synthesized by highly stereospecific reactions from 2-(2-tert-butyldimethylsilyloxyethyl)- and 2-[2-(4-methoxybenzyloxy)-ethyl]-5-arylpenta-2E,4E-dien-1-ols. These dienols were efficiently dehydroxylated to (1E,3Z)-4-methyl-6-(4-methoxybenzyloxy)hexa-1,3-dienylarenes with their subsequent demethoxyben-zylation to (3Z,5E)-6-aryl-3-methylhexa-3,5-dien-1-ols. The latter through the step of corresponding aryldienals and aryldienoic acids were transformed to the target methyl (3Z,5E)-6-aryl-3-methylhexa-3,5-dienoates, which completes a formal synthesis of strobilurins A and X. Configuration of the C=C bonds of the conjugated aryldiene system is preserved in the considered transformations by 95–97%.     

Cycloaddition of Dialkylalumanyl Anion toward Unsaturated Hydrocarbons in (1+2) and (1+4) Modes

The reactivity of dialkylalumanyl anion ( 1 ) towards naphthalene, anthracene, diphenylacetylene, and (E)/(Z)-stilbenes was investigated. The compound 1 reacts with naphthalene and anthracene through (1+4) cyclization, giving Al-containing norbornadiene derivatives. In the reaction of 1 with diphenylacetylene and (E)/(Z)-stilbenes, (1+2) cyclization proceeded to form Al-C-C three-membered rings. Cyclization toward (E)- or (Z)-stilbenes solely gave a trans-cycloadduct. DFT calculations revealed that the cycloaddition of 1 with (Z)-stilbene proceeds via a single transition state with a carbanion character, which results in the selectivity towards the trans-cycloadduct.     

Isolation of Toxic and Potentially Toxic Sesqui- and Monoterpenes from the Tropical Green Seaweed Caulerpa taxifolia Which Has Invaded the Region of Cap Martin and Monaco

The green seaweed Caulerpa taxifolia (VAHL ) C. AGARDH (Caulerpales), which, after its recent accidental introduction, is growing in the region of Cap Martin much more vigorously than in the tropics, is shown to contain the known sesquiterpenic toxins caulerpenyne ( 1 ) – in larger amounts than in tropical Caulerpales – and oxytoxin 1 ( 2 ). Novel, potentially toxic products isolated in small amounts from this seaweed include the sesquiterpenes taxifolial A ( = (5E)-6,10-dimethyl-2-[(E)2-oxoethylidene]undeca-5,9-dien-7- yne-1,3-diyl diacetate; 3 ), taxifolial B (= (1E,6E,10E)-3-[( Z )-acetoxymethylidene]-7, 11-dimethyl-12-oxododeca-1,6,10-trien-8-yne-1,4-diyl diacetate; 4 ), 10,11-epoxycaulerpenyne ( = (1E,6E)-3-[(Z)-acetoxymethylidene]-10,11-epoxy-7, 11-dimethyldodeca-1,6-dien-8-yne-1,4-diyl diacetate; 1:1 diastereoisomer mixture; 5 ), and taxifolial C ( = (2Z,6E)-3-formyl-7,11-dimethyldodeca-2,6,10-trien-8-yne-1,1, 4-triyl triacetate; 6 ), besides, as the first example of a monoterpene from the Caulerpales, taxifolial D ( = (2Z)-3,7-dimethylocta-2, 6-dien-4-ynal; 7 ).     

Synthesis of spiro[4.5]decane and bicyclo[4.3.0]nonane ring systems by self-cyclization of (Z)- and (E)-2-(trimethylsilylmethyl)pentadienal derivative

The two title carbon frameworks were synthesized utilizing a new type of iron-induced cyclization reaction of 2-(trimethylsilylmethyl)pentadienal. 2-Methylspiro[4.5]dec-2-en-1-one was obtained from (Z)- and (E)-4-cyclohexylidene-2-(trimethylsilylmethyl)but-2-enal. It was found that the (Z)-substrate isomerized to (E)-intermediate followed by cyclization to afford the initial product, 2-methylenespiro[4.5]dec-3-en-1-ol, which was isomerized to the above product. The cyclization of 4-(4-alkyl)cyclohexylidene-2-(trimethylsilylmethyl)but-2-enal proceeded stereoselectively. While, (E)-3-(cyclohex-1-en-1-yl)-2-(trimethylsilylmethyl)prop-2-en-1-al cyclized immediately affording 8-methylenebicyclo[4.3.0]non-9-en-7-ol. The corresponding (Z)-isomer gave several cyclization products as a complex mixture.     

Methyl (<Emphasis Type="Italic">Z</Emphasis>)-3-bromo-3-(4-methylbenzenesulfonyl)prop-2-enoate: Synthesis and reactions with dimethyl malonate and methyl acetoacetate

Bromination–dehydrobromination of methyl (E)-3-(4-methylbenzenesulfonyl)prop-2-enoate gave methyl (Z)-3-bromo-3-(4-methylbenzenesulfonyl)prop-2-enoate whose structure was determined by X-ray analysis. Methyl (Z)-3-bromo-3-(4-methylbenzenesulfonyl)prop-2-enoate behaved as a synthetic equivalent of methyl 3-(4-methylbenzenesulfonyl)prop-2-ynoate in reactions with dimethyl malonate and methyl acetoacetate, which afforded the corresponding Michael adducts, trimethyl 3-(4-methylbenzenesulfonyl)prop-1-ene-1,1,2-tricarboxylate and dimethyl (Z)-2-acetyl-3-(4-methylbenzenesulfonyl)but-2-enedioate, respectively, via nucleophilic attack on the β-position with respect to the sulfonyl group.     

Polar Metabolites of the Tropical Green Seaweed Caulerpa taxifolia Which Is Spreading in the Mediterranean Sea: Glycoglycerolipids and Stable Enols (α\=Keto Esters)

Examination of the polar components of the green seaweed Caulerpa taxifolia (Vahl ) C. Agardh , which is heavily spreading in the northeastern Mediterranean, led to two families of compounds. The new (2R)-3-O-β-D -galactopyranosyl-1-O-[(7Z,10Z,13Z)-hexadeca-7,10,13-trienoyl]-2-O-[(9Z,12Z,15Z)-octadeca-1,12,15-trienoyl]-sn-glycerol ( 2 ) was isolated in low abundance, like the analogues 1 and 3 already known from freshwater cyanobacteria. The acyl positions in 1 – 3 were determined by enzymatic methods and the absolute configuration from the O-galactosylglycerol obtained upon alcaline methanolysis. More abundant were the (4-hydroxyphenyl)- and (3,4-dihydroxyphenyl)pyruvic acid methyl esters, occurring in the enol (Z) forms 13a and 14a accompanied by very minor (E) forms 13b and 14b . The latter became predominant on UV irradiation of 13a or 14a , allowing the determination of the C=C configuration of these isolatable, stable enols from ¹H,¹³C NMR couplings (larger H−C(3)/C(1) coupling constant in the (E) than in the (Z) isomer). Contrary to literature implications, the O-galactosylglycerolipids 1 – 3 lack any cholinergic or histaminergic activity; similarly, enols (= α-keto esters) 13 and 14 or terpenoids of this seaweed were also devoid of such biological activities (see Table).     

Azimine IV. Kinetik und Mechanismus der thermischen Stereoisomerisierung von 2,3-Diaryl-1-phthalimido-aziminen

Azimines IV. Kinetics and Mechanism of the Thermal Stereoisomerization of 2,3-Diaryl-1-phthalimido-azimines¹) Mixtures of (1E, 2Z)- and (1Z, 2E)-2-phenyl-1-phthalimido-3-p-tolyl-azimine ( 3a and 3b , resp.) and (1E, 2Z)- and (1Z, 2E)-3-phenyl-1-phthalimido-2-p-tolylazimine ( 4a and 4b , resp.) were obtained by the addition of oxidatively generated phthalimido-nitrene (6) to (E)- and (Z)-4-methyl-azobenzene ( 7a and 7b , resp.). Whereas complete separation of the 4 isomers 3a, 3b, 4a and 4b was not possible, partial separation by chromatography and crystallization led to 5 differently composed mixtures of azimine isomers. The spectroscopic properties of these mixtures (UV., ¹H-NMR.) were used to determine the ratios of isomers in the mixtures, and served as a tool for the assignment of constitution and configuration to those isomers which were dominant in each of these mixtures, respectively. Investigation of the isomerization of the azimines 3a, 3b, 4a and 4b within the 5 mixtures at various concentrations by ¹H-NMR.-spectroscopy at room temperature revealed that only stereoisomers are interconverted ( 3a ? 3b; 4a ? 4b) and that the (1E, 2Z) ? (1Z, 2E) stereoisomerization is a unimolecular reaction. These observations exclude an isomerization mechanism via an intermediate 1-phthalimido-triaziridine (2) or via dimerization of 1-phthalimido-azimines (1) , respectively. The 3-p-tolyl substituted stereoisomers 3a and 3b isomerized slightly slower than the 3-phenyl substituted ones 4a and 4b , an effect which is consistent with the assumption that the rate determining step of the interconversion of (1E, 2Z)- and (1Z, 2E)-1-phthalimido-azimines (1a ? 1b) is the stereoisomerization of the stereogenic center at N(2), N(3), either by inversion of N(3) or by rotation around the N(2), N(3) bond. The total isomerization process is assumed to occur via the thermodynamically less stable (1Z, 2Z)- and (1E, 2E)-isomers 1c and 1d , respectively, as intermediates in undetectably low concentrations which stay in rapidly established equilibria with the observed, thermodynamically more stable (1E, 2Z)- and (1Z, 2E)-isomers 1a and 1b , respectively. At higher temperatures, the azimines 3 and 4 are transformed into N-phenyl-N,N′-phthaloyl-N′-p-tolyl-hydrazine (8) with loss of nitrogen.