Synthese und Reaktivität von 2‐Brom‐1,3‐diethyl‐2,3‐dihydro‐1 H‐1,3,2‐benzodiazaborol Molekülstruktur von Bis(1,3‐diethyl‐2,3‐dihydro‐1 H‐1,3,2‐benzodiazaborol‐2‐yl)

Synthesis and Reactivity of 2‐Bromo‐1,3‐diethyl‐2,3‐dihydro‐1 H ‐1,3,2‐benzodiazaborole Molecular Structure of Bis(1,3‐diethyl‐2,3‐dihydro‐1 H ‐1,3,2‐benzodiazaborol‐2‐yl The reaction of a slurry of calcium hydride in toluene with N,N′‐diethyl‐o‐phenylenediamine ( 1 ) and boron tribromide affords 2‐bromo‐1,3‐diethyl‐2,3‐dihydro‐1 H‐1,3,2‐benzodiazaborol ( 2 ) as a colorless oil. Compound 2 is converted into 2‐cyano‐1,3‐diethyl‐2,3‐dihydro‐1 H‐1,3,2‐benzodiazaborole ( 3 ) by treatment with silver cyanide in acetonitrile. Reaction of 2 with an equimolar amount of methyllithium affords 1,3‐diethyl‐2‐methyl‐2,3‐dihydro‐1 H‐1,3,2‐benzodiazaborole ( 4 ). 1,3,2‐Benzodiazaborole is smoothly reduced by a potassium‐sodium alloy to yield bis(1,3‐diethyl‐2,3‐dihydro‐1 H‐1,3,2‐benzodiazaborol‐2‐yl] ( 7 ), which crystallizes from n‐pentane as colorless needles. Compound 7 is also obtained from the reaction of 2 and LiSnMe₃ instead of the expected 2‐trimethylstannyl‐1,3,2‐benzodiazaborole. N,N′‐Bis(1,3‐diethyl‐2,3‐dihydro‐1 H‐1,3,2‐benzodiazaborol‐2‐ yl)‐1,2‐diamino‐ethane ( 6 ) results from the reaction of 2 with Li(en)C≡CH as the only boron containing product. Compounds 2 – 4 , 6 and 7 are characterized by means of elemental analyses and spectroscopy (IR, ¹H‐, ¹¹B{¹H}‐, ¹³C{¹H}‐NMR, MS). The molecular structure of 7 was elucidated by X‐ray diffraction analysis.     

The low‐melting compounds 1,4‐diethyl‐, 1,2‐diethyl‐ and ethylbenzene

Crystals of 1,4‐diethyl‐ and 1,2‐diethylbenzene, both C₁₀H₁₄, and ethylbenzene, C₈H₉, have been grown in situ. The molecules of 1,4‐diethyl‐ and 1,2‐diethylbenzene are located about a centre of inversion and across a twofold axis, respectively. In both molecules, the terminal methyl groups are located on opposite sides of the plane of the aromatic ring. In the crystal structures of all three compounds, molecules are linked together by (Ar)C—H...π and CH₂...π contacts. The methyl H atoms do not form close contacts with any of the aromatic π systems.     

Supramolecular structures of bis‐thionooxalamic acid esters derived from (±)‐cyclohexane‐1,2‐diamine and (±)‐1,2‐diphenylethylenediamine

The bis‐thionooxalamic acid esters trans‐(±)‐diethyl N,N′‐(cyclohexane‐1,2‐diyl)bis(2‐thiooxamate), C₁₄H₂₂N₂O₄S₂, and (±)‐N,N′‐diethyl (1,2‐diphenylethane‐1,2‐diyl)bis(2‐thiooxamate), C₂₂H₂₄N₂O₄S₂, both consist of conformationally flexible molecules which adopt similar conformations with approximate C₂ rotational symmetry. The thioamide and ester parts of the thiooxamate group are significantly twisted along the central C—C bond, with the S=C—C=O torsion angles in the range 30.94 (19)–44.77 (19)°. The twisted s‐cis conformation of the thionooxamide groups facilitates assembly of molecules into a one‐dimensional polymeric structure via intermolecular three‐center C=S...NH...O=C hydrogen bonds and C—H...O interactions formed between molecules of the opposite chirality.     

2‐Ethyl‐1‐[5‐(4‐methylphenyl)pyrazol‐3‐yl]‐3‐(thiophene‐2‐carbonyl)isothiourea: molecular ribbons containing three types of hydrogen‐bonded ring

The title compound, C₁₈H₁₈N₄OS₂, was prepared by reaction of S,S‐diethyl 2‐thenoylimidodithiocarbonate with 5‐amino‐3‐(4‐methylphenyl)‐1H‐pyrazole using microwave irradiation under solvent‐free conditions. In the molecule, the thiophene unit is disordered over two sets of atomic sites, with occupancies of 0.814 (4) and 0.186 (4), and the bonded distances provide evidence for polarization in the acylthiourea fragment and for aromatic type delocalization in the pyrazole ring. An intramolecular N—H...O hydrogen bond is present, forming an S(6) motif, and molecules are linked by N—H...O and N—H...N hydrogen bonds to form a ribbon in which centrosymmetric R₂²(4) rings, built from N—H...O hydrogen bonds and flanked by inversion‐related pairs of S(6) rings, alternate with centrosymmetric R₂²(6) rings built from N—H...N hydrogen bonds.     

A convenient synthesis of novel 7‐phosphonylbenzyl‐2‐substituted pyrazolo[4,3‐e]‐1,2,4‐triazolo[1,5‐c]‐pyrimidine derivatives

A series of pyrazolo[4,3‐e]‐1,2,4‐triazolo‐[1,5‐c]pyrimidine derivatives, bearing phosphonylbenzyl chain in position 7, were conveniently synthesized in an attempt to obtain potent and selective antagonists for the A_2A adenosine receptor or potent pesticide lead compounds. Diethyl[(5‐amino‐4‐cyano‐3‐methylsulfanyl‐pyrazol‐1‐yl)‐benzyl]phospho‐nate ( 3 ), which was prepared by the cyclization of diethyl 1‐hydrazinobenzylphosphonate ( 1 ) with 2‐[bis(methylthio)methylene]malononitrile ( 2 ), reacted with triethyl orthoformate to afford diethyl[(4‐cyano‐5‐ethoxymethyleneamino‐3‐methylsulfanyl‐pyrazol‐1‐yl)‐benzyl]phosphonate ( 4 ), which reacted with various acyl hydrazines in refluxing 2‐methoxyethanol to give the target compounds 5a–h in good yields. Their structures were confirmed by IR, ¹H NMR, ¹³C NMR, MS, and elemental analysis. The crystal structure of 5e was determined by single crystal X‐ray diffraction © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:634–638, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20478     

Synthesis of 5‐[2‐(guanin‐9‐yl)‐ and 5‐[2‐(2‐aminopurin‐9‐yl)ethyl]‐2‐D‐ribo‐(1,2′,3′,4′‐tetrahydroxybutyl)‐1,3‐dioxane

Stereoselective synthesis of 5‐[2‐(guanin‐9‐yl)‐ and 5‐[2‐(2‐aminopurin‐9‐yl)ethyl]‐2‐D‐ribo‐(1′,2′,3′,4′‐tetrahydroxybutyl)‐1,3‐dioxane, 2‐5, as potential prodrugs of penciclovir, has been accomplished in six steps from readily available 2,3,4,5‐tetra‐O‐acetyl‐aldehydo‐D‐ribose ( 6 ) and the 1,3‐diol 7 . It has been demonstrated that the use of boron trifluoride diethyl etherate (BF₃·Et₂O) in dichloromethane along with excess anhydrous copper(II) sulfate was crucial for the efficient formation of cyclic acetal 8 . In addition, the chromatographic separation of cis and trans isomers of the cyclic acetal at the bromide stage 10 was feasible, which was requisite for the successful stereoselective synthesis of the ribosyl derivatives 2–5 .     

1,1′‐Diethyl‐4,4′‐bipyridine‐1,1′‐diium bis(1,1,3,3‐tetracyano‐2‐ethoxypropenide): multiple C—H...N hydrogen bonds form a complex sheet structure

In the title salt, C₁₄H₁₈N₂²⁺·2C₉H₅N₄O⁻, the 1,1′‐diethyl‐4,4′‐bipyridine‐1,1′‐diium dication lies across a centre of inversion in the space group P2₁/c. In the 1,1,3,3‐tetracyano‐2‐ethoxypropenide anion, the two independent –C(CN)₂ units are rotated, in conrotatory fashion, out of the plane of the central propenide unit, making dihedral angles with the central unit of 16.0 (2) and 23.0 (2)°. The ionic components are linked by C—H...N hydrogen bonds to form a complex sheet structure, within which each cation acts as a sixfold donor of hydrogen bonds and each anion acts as a threefold acceptor of hydrogen bonds.     

Synthesis,Structural Characterization,Photophysics, and Broadband Nonlinear Absorption of a Platinum(II) Complex with the 6‐(7‐Benzothiazol‐2′‐yl‐9,9‐diethyl‐9 H‐fluoren‐2‐yl)‐2,2′‐bipyridinyl Ligand

A platinum complex with the 6‐(7‐benzothiazol‐2′‐yl‐9,9‐diethyl‐9H‐fluoren‐2‐yl)‐2,2′‐bipyridinyl ligand ( 1 ) was synthesized and the crystal structure was determined. UV/Vis absorption, emission, and transient difference absorption of 1 were systematically investigated. DFT calculations were carried out on 1 to characterize the electronic ground state and aid in the understanding of the nature of low‐lying excited electronic states. Complex 1 exhibits intense structured ¹π–π* absorption at λ_abs<440 nm, and a broad, moderate ¹M LCT/¹LLCT transition at 440–520 nm in CH₂Cl₂ solution. A structured ³π–π*/³M LCT emission at about 590 nm was observed at room temperature and at 77 K. Complex 1 exhibits both singlet and triplet excited‐state absorption from 450 nm to 750 nm, which are tentatively attributed to the ¹π–π* and ³π–π* excited states of the 6‐(7‐benzothiazol‐2′‐yl‐9,9‐diethyl‐9H‐fluoren‐2‐yl)‐2,2′‐bipyridine ligand, respectively. Z‐scan experiments were conducted by using ns and ps pulses at 532 nm, and ps pulses at a variety of visible and near‐IR wavelengths. The experimental data were fitted by a five‐level model by using the excited‐state parameters obtained from the photophysical study to deduce the effective singlet and triplet excited‐state absorption cross sections in the visible spectral region and the effective two‐photon absorption cross sections in the near‐IR region. Our results demonstrate that 1 possesses large ratios of excited‐state absorption cross sections relative to that of the ground‐state in the visible spectral region; this results in a remarkable degree of reverse saturable absorption from 1 in CH₂Cl₂ solution illuminated by ns laser pulses at 532 nm. The two‐photon absorption cross sections in the near‐IR region for 1 are among the largest values reported for platinum complexes. Therefore, 1 is an excellent, broadband, nonlinear absorbing material that exhibits strong reverse saturable absorption in the visible spectral region and large two‐photon‐assisted excited‐state absorption in the near‐IR region.     

1,1‐Diethyl‐1‐germa‐2,3,4,5‐tetra‐tert‐butyl‐2,3,4,5‐tetraphospholan (C2H5)2Ge(tBuP)4, Molekül‐ und Kristallstruktur

1,1‐Diethyl‐1‐germa‐2,3,4,5‐tetra‐ tert ‐butyl‐2,3,4,5‐tetraphospholane (C₂H₅)₂Ge( t BuP)₄, Molecular and Crystal Structure The reaction of the diphosphide K₂[(tBuP)₄] · THF ( 1 ) with the germanium(IV) compound (C₂H₅)₂GeCl₂ leads via a [4 + 1]‐cyclo‐condensation reaction to 1,1‐diethyl‐1‐germa‐2,3,4,5‐tetra‐tert‐butyl‐2,3,4,5‐tetraphospholane (C₂H₅)₂Ge(tBuP)₄ ( 2 ) with the 5‐membered GeP₄ ring system. 2 could be characterized ³¹P NMR spectroscopically, mass spectrometrically and by a single crystal structure analysis.     

Synthesis of 2‐amino‐s‐triazino[1,2‐a]benzimidazoles as potential antifolates from 2‐guanidino‐ and 2‐guanidino‐5‐methylbenzimidazoles

The syntheses of 2‐amino‐s‐triazino[1,2‐a]benzimidazoles from 2‐guanidinobenzimidazoles were successfully carried out by a ring annelation reaction. The regiochemistry of the ring closure of 5‐methyl‐2‐guanidinobenzimidazole with diethyl azodicarboxylate, aldehydes, acetone, diethyl ethoxymethylenemalonate and orthoesters, leading to the formation of s‐triazine ring was studied. High regioselectivity was not observed in any of these reactions. However, the synthesis of s‐triazino[1,2‐a]benzimidazole system was found to be more regioselective than its 3,4‐dihydro analogue. NOESY experiment indicated that the compound, 2‐amino‐4,4‐dimethyl‐3,4‐dihydro‐s‐triazino[1,2‐a]benzimidazole existed predominantly as the 3,4‐dihydro tautomer in dimethyl sulfoxide. It was found to inhibit bovine dihydrofolate reductase with IC₅₀ 10.9 μM.     

Sequential Intramolecular Diels–Alder Reaction of 3‐Heteroaryl‐2‐propenylamides of Ethenetricarboxylate

The reaction of 1,1,2‐ethenetricarboxylic acid 1,1‐diethyl ester with E‐3‐(2‐furyl)‐2‐propenylamines under the amide condensation conditions (EDCI/HOBt/Et₃N) on heating at 80–110°C afforded cis‐fused tricyclic compounds, furo[2,3‐f]isoindoles as major product. On the other hand, the reaction with E‐3‐(3‐furyl)‐2‐propenylamines afforded trans‐fused tricyclic compounds predominantly. The formation of amide/[4 + 2] cycloaddition/hydrogen‐shift reactions proceed sequentially. The observed stereoselectivity of the fused rings has been investigated by the density functional theory calculations. The reaction of 1,1,2‐ethenetricarboxylic acid 1,1‐diethyl ester with 3‐(3‐pyridinyl)‐2‐propen‐1‐amine under the amide condensation conditions afforded HOBt‐incorporated 3,4‐trans‐pyrrolidine selectively. The chemoselectivity and stereoselectivity of the reactions with (3‐heteroaryl)‐2‐propen‐1‐amines depend on the nature of heteroarenes.     

A doubly bridged isodicyclopentadienyl zirconium complex: bis{N‐(3,5‐dimethylphenyl)‐N‐[(η5‐isodicyclopentadien‐2‐yl)dimethylsilyl]amido‐κN}zirconium(II) diethyl ether solvate

Transmetallation of the dilithium salt of (3,5‐dimethyphenyl­amino)(isodicyclopentadienyl)dimethylsilane by treatment with zirconium tetrachloride in a 2:1 ratio leads to the substitution of all four chloride ligands. With the applied stoichiometry, the title complex, [Zr(C₂₀H₂₅NSi)₂]·C₄H₁₀O, was obtained and crystallized from diethyl ether. X‐ray diffraction characterization showed that both isodi­cyclo­penta­dienyl ligands (alternatively called 4,5,6,7‐tetrahydro‐4,7‐methano‐1H‐indene) are complexed to the metal on their exo face in a completely stereoselective manner and that they are η⁵‐bonded to the Zr atom.     

A Convenient Synthetic Route of Diethyl (4‐Oxo‐chromeno[2,3‐d]pyrimidin‐2(5)‐yl)phosphonates

Novel diethyl (4‐oxo‐3,4‐dihydro‐2H‐chromeno[2,3‐d]pyrimidin‐2‐yl)phosphonate as two enantiomers and diethyl (4‐oxo‐1,5‐dihydro‐4H‐chromeno[2,3‐d]pyrimidin‐5‐yl) phosphonate were obtained in easy procedure via reaction of 2‐imino‐2H‐chromene‐3‐carboxamide, dimethylformamide dimethyl‐acetal, and diethyl phosphite in a simple one pot. Possible reaction mechanisms were proposed. The structures of the obtained products were confirmed by elemental analyses and spectral tools.     

Crystallization experiments with the dinuclear chelate ring complex di‐μ‐chlorido‐bis[(η2‐2‐allyl‐4‐methoxy‐5‐{[(propan‐2‐yloxy)carbonyl]methoxy}phenyl‐κC1)platinum(II)]

Crystallization experiments with the dinuclear chelate ring complex di‐μ‐chlorido‐bis[(η²‐2‐allyl‐4‐methoxy‐5‐{[(propan‐2‐yloxy)carbonyl]methoxy}phenyl‐κC¹)platinum(II)], [Pt₂(C₁₅H₁₉O₄)₂Cl₂], containing a derivative of the natural compound eugenol as ligand, have been performed. Using five different sets of crystallization conditions resulted in four different complexes which can be further used as starting compounds for the synthesis of Pt complexes with promising anticancer activities. In the case of vapour diffusion with the binary chloroform–diethyl ether or methylene chloride–diethyl ether systems, no change of the molecular structure was observed. Using evaporation from acetonitrile (at room temperature), dimethylformamide (DMF, at 313 K) or dimethyl sulfoxide (DMSO, at 313 K), however, resulted in the displacement of a chloride ligand by the solvent, giving, respectively, the mononuclear complexes (acetonitrile‐κN)(η²‐2‐allyl‐4‐methoxy‐5‐{[(propan‐2‐yloxy)carbonyl]methoxy}phenyl‐κC¹)chloridoplatinum(II) monohydrate, [Pt(C₁₅H₁₉O₄)Cl(CH₃CN)]·H₂O, (η²‐2‐allyl‐4‐methoxy‐5‐{[(propan‐2‐yloxy)carbonyl]methoxy}phenyl‐κC¹)chlorido(dimethylformamide‐κO)platinum(II), [Pt(C₁₅H₁₉O₄)Cl(C₂H₇NO)], and (η²‐2‐allyl‐4‐methoxy‐5‐{[(propan‐2‐yloxy)carbonyl]methoxy}phenyl‐κC¹)chlorido(dimethyl sulfoxide‐κS)platinum(II), determined as the analogue {η²‐2‐allyl‐4‐methoxy‐5‐[(ethoxycarbonyl)methoxy]phenyl‐κC¹}chlorido(dimethyl sulfoxide‐κS)platinum(II), [Pt(C₁₄H₁₇O₄)Cl(C₂H₆OS)]. The crystal structures confirm that acetonitrile interacts with the Pt^II atom via its N atom, while for DMSO, the S atom is the coordinating atom. For the replacement, the longest of the two Pt—Cl bonds is cleaved, leading to a cis position of the solvent ligand with respect to the allyl group. The crystal packing of the complexes is characterized by dimer formation via C—H…O and C—H…π interactions, but no π–π interactions are observed despite the presence of the aromatic ring.     

Bicyclic [b]‐heteroannulated pyridazine derivatives. 9. cyclization reactions of 4,4‐dimethyl‐ and 4‐phenyltetrahydropyridazine‐3,6‐dione 3‐hydrazones with esters of keto dicarboxylic acids

Bis(ethoxycarbonyl)alkylidene derivatives 4 and 5 of the respective title hydrazones were obtained in the reactions with diethyl oxomalonate, diethyl oxosuccinate, diethyl 2‐oxoglutarate, and diethyl oxalo‐propionate as mixtures of geometric isomers with high predominance of one of them. On heating at 160‐200° without any solvent or on refluxing in ethanol 4 cyclized to yield the corresponding pyri‐dazino[6, 1‐c]triazines 6 , whereas heating of 5 gave, depending on the chain length, the corresponding pyra‐zolylpyridazines 8b and 8d or the pyridazinylpyridazine 8c . X‐ray analysis was used to determine the structures of 6 and 8 ; the unit cell of 6c was found to accommodate 16 molecules representing four conforma‐tional varieties. The different behavior of 4 and 5 in the cyclization reactions was interpreted in terms of the tautomeric equilibrium which was shifted towards the enamine form in 4 , and towards the imine form, in 5 . Transmission of a long‐range chirality effect in 4d and 5a‐d manifested itself in the ¹H nmr spectra as the magnetic non‐equivalence of the CH₂ protons in one or both ester ethyl groups.     

Tetrakis(diethyl‐phosphonat)‐, Tetrakis(ethyl‐phenylphosphinat)‐ und Tetrakis(diphenylphosphin‐oxid)‐substituierte Phthalocyanine

Tetrakis(diethyl phosphonate), Tetrakis(ethyl phenylphosphinate)‐, and Tetrakis(diphenylphosphine oxide)‐Substituted Phthalocyanines The title compounds 7, 9 , and 11 are obtained by tetramerization of diethyl (3,4‐dicyanophenyl)phosphonate ( 5 ), ethyl (3,4‐dicyanophenyl)phenylphosphinate ( 8 ), and 4‐(diphenylphosphinyl)benzene‐1,2‐dicarbonitrile ( 10 ). The ³¹P‐NMR spectra of the phthalocyanines 7, 9 , and 11 and of their metal complexes present five to eight signals confirming the formation of four constitutional isomers with the expected C_4h, D_2h, C_2v, and C_s symmetry. In the FAB‐MS of the Zn, Cu, and Ni complexes of 7 and 9 , the peaks of dimeric phthalocyanines are observed. By gel‐permeation chromatography, the monomeric complex [Ni( 7 )] and a dimer [Ni( 7 )]₂ can be separated. These dimers differ from the known phthalocyanine dimers, i.e., possibly the P(O)(OEt)₂ and P(O)(Ph)(OEt) substituents in 7 and 9 are involved in complexation. The free phosphonic acid complex [Zn( 12 )] and [Cu( 12 )] are H₂O‐soluble. In the FAB‐MS of [Zn( 12 )], only the peaks of the dimer are present; the ESI‐MS confirms the existence of the dimer and the metal‐free dimer. In the UV/VIS spectrum of [Zn( 12 )], the hypsochromic shift characteristic for the known type of dimers from 660–700 nm to 620–640 nm is observed. As in the FAB‐MS of [Zn( 12 )], the free phosphinic acid complex [Zn( 13 )] shows only the monomer, an ESI‐MS cannot be obtained for solubility problems. The UV/VIS spectrum of [Zn( 13 )] demonstrates the existence of the monomer as well as of the dimer.     

Bis(N,N‐diethyl‐1,1‐di­seleno­carbam­ato‐Se)­selenium, [(Se2CNEt2)2Se]

The poly­seleno title compound, bis(N,N‐diethyl­seleno­carbamoyl) tri­selenide, [(Se₂CNEt₂)₂Se] or C₁₀H₂₀N₂Se₅, is obtained from the disproportion of sodium N,N‐diethyl‐1,1‐di­seleno­carbamate. An Se atom connects two N,N‐diethyl‐1,1‐di­seleno­carbamate groups with Se—Se distances in the range 2.4500 (11)–2.8601 (12) Å     

Experimental and Theoretical Studies of Bromination of Diethyl 2,4,6‐Trimethyl‐1,4‐dihydropyridine‐3,5‐dicarboxylate

A reaction of diethyl 2,4,6‐trimethyl‐1,4‐dihydropyridine‐3,5‐dicarboxylate with 1, 2, and more equivalents of N‐bromosuccinimide (NBS) in methanol was investigated by NMR spectroscopy at a temperature interval ranging from 25 to 40°C. The reaction was found to proceed through several steps. The structures of the intermediates diethyl 3‐bromo‐2,4,6‐trimethyl‐3,4‐dihydropyridine‐3,5‐dicarboxylate, diethyl 3‐bromo‐2‐methoxy‐2,4,6‐trimethyl‐1,2,3,4‐tetrahydropyridine‐3,5‐dicarboxylate, and diethyl 3,5‐dibromo‐2‐methoxy‐2,4,6‐trimethyl‐2,3,4,5‐tetrahydropyridine‐3,5‐dicarboxylate were identified by multinuclear (¹H, ¹³C, and ¹⁵N) NMR spectral data. The optimal structures of all species participating in the reaction as well as changes in their relative energies along with the proposed pathway of the reaction were analyzed by quantum‐chemical calculations. The mechanism of bromination of diethyl 2,4,6‐trimethyl‐1,4‐dihydropyridine‐3,5‐dicarboxylate with NBS in methanol was found to favor the bromination in the 2,6‐methyl side chains as the only products in full agreement with experimental observations.     

氯化铁:一类高效的催化剂用于三组份反应合成α-氨基膦酸酯类化合物

Three-component reactions of aldehydes,amines,and diethyl phosphite catalyzed by FeCl_3 in EtOH or undersolvent-free and mild conditions afforded the corresponding α-amino phosphonates in excellent yields.     

Synthesis and Structure of O,O‐Diethyl N‐[(trans‐4‐Aryl‐5,5‐dimethyl‐2‐oxido‐2λ5‐1,3,2‐dioxaphosphorinan‐2‐yl)methyl]phosphoramidothioates

A study on the synthesis of the novel N‐(cyclic phosphonate)‐substituted phosphoramidothioates, i.e., O,O‐diethyl N‐[(trans‐4‐aryl‐5,5‐dimethyl‐2‐oxido‐2λ⁵‐1,3,2‐dioxaphosphorinan‐2‐yl)methyl]phosphoramidothioates 4a – l , from O,O‐diethyl phosphoramidothioate ( 1 ), a benzaldehyde or ketone 2 , and a 1,3,2‐dioxaphosphorinane 2‐oxide 3 was carried out (Scheme 1 and Table 1). Some of their stereoisomers were isolated, and their structure was established. The presence of acetyl chloride was essential for this reaction and accelerated the process of intramolecular dehydration of intermediate 5 forming the corresponding Schiff base 7 (Scheme 2).