Phosphorylation of 2‐(3‐methyl‐1,3‐diazabuten‐1‐yl)‐3‐ethoxycarbonylthiophenes with phosphorus(III) halides

2‐(3‐Methyl‐1,3‐diazabuten‐1‐yl)‐3‐ethoxycarbonylthiophenes are phosphorylated with phosphorus(III) halides in basic media at position 5 of the thiophene ring. Up to three heteroaromatic substituents can be introduced one by one at the same phosphorus atom. On this basis, mono‐, bis‐, and trishetaryl substituted P(III) and P(V) derivatives have been obtained. Phosphorylated 2‐(N,N‐dimethylformamidino)‐3‐ethoxycarbonylthiophenes provide a synthetic access to phosphorylated thienopyrimidines. © 2001 John Wiley & Sons, Inc. Heteroatom Chem 12:641–651, 2001     

Enantioselective reduction of 2‐keto‐3‐haloalkane phosphonates by baker's yeast

Bioreduction of 3‐substituted‐2‐oxoal‐kanephosphonates by baker's yeast afforded 3‐substituted‐2‐hydroxy‐alkanephosphonates in moderate to good yields and ee value. These compounds could serve as useful chirons for the stereoselective synthesis of phosphorus analogs of biologically active molecules including R‐(—)‐3‐trimethylammonium‐2‐hydroxypropanoic acid and R‐(—)‐3‐ trimethylammonium‐2‐hydroxypropanoic acid. © 2001 John Wiley & Sons, Inc. Heteroatom Chem 12:551–556, 2001     

The reaction of 2‐amino‐3‐cyano‐4,5,6,7‐tetrahydrobenzo[b]‐thiophene with diethyl malonate: synthesis of coumarin,pyridine, and thiazole derivatives

The reaction of 2‐amino‐3‐cyano‐4,5,6,7‐tetrahydrobenzo[b]thiophene ( 1 ) with diethyl malonate ( 2 ) gave two products: 3 and 4 . The reactivity of 3 toward a variety of chemical reagents was studied to give azoles, azines, and their fused derivatives. © 2001 John Wiley & Sons, Inc. Heteroatom Chem 12:168–175, 2001     

Reaction with hydrazonoyl halides. Part 32 [1]: Reaction of C‐acyl‐N‐(3‐phenyl‐5‐pyrazolyl)hydrazonoyl chlorides with potassium thiocyanate and synthesis of some new 2,3‐dihydro‐1,3,4‐thiadiazoles and slenadiazoles

C‐acyl‐N‐(3‐phenyl‐5‐pyrazolyl)hydrazonoyl chlorides 1a,b react with potassium thiocyanate and potassium selenocyanate to give 5‐acyl‐2,3‐dihydro‐2‐imino‐3‐(3′‐phenyl)pyrazol‐5′‐yl)‐1,3,4‐thiadiazoles 2a,b and 5‐acetyl‐2,3‐dihydro;‐2‐imino‐3‐(3′‐phenyl)pyrazol‐5′‐yl)‐1,3,4‐selenadiazole 10a,b . Also, 2‐[mercapto‐(methylthio)methylene]indan‐1,3‐dione 16 reacts with hydrazonoyl halides 15 and 22–25 to afford 2,3‐dihydro‐1,3,4‐thiadiazoles 19 and 26–29 , respectively. Structures of the newly synthesized compounds are elucidated on the basis of spectral data, chemical transformations, and alternative synthesis methods. © 2001 John Wiley & Sons, Inc. Heteroatom Chem 12:468–474, 2001     

Reactions of 2,3‐dihydro‐1H‐1,5‐benzodiazepines and chloroacetyl chlorides: Synthesis of 2a,3,4,5‐tetrahydro‐azeto [1,2‐a][1,5] benzodiazepin‐1(2H)‐ones

2a,4‐Disubstituted 5‐benzoyl‐2‐chloro/2,2‐dichloro‐2a,3,4,5‐tetrahydro‐azeto [1,2‐a] [1,5]benzodiazepin‐1 (2H)‐ones ( 3a–h ) were synthesized by cycloaddition reactions of 2,4‐disubstituted 1‐benzoyl‐2,3‐dihydr o‐1H‐1,5‐benzodiazepines ( 2a–h ) and ketenes, generated from chloroacetyl chloride or dichloroacetyl chloride in the presence of triethylamine, in anhydrous benzene. In some cases, ring contraction of benzodiazepines has also been observed. © 2001 John Wiley & Sons, Inc. Heteroatom Chem 12:636–640, 2001     

Gas‐phase pyrolysis of 2‐heteroaromatic‐1‐dimethylaminoethylenes: Kinetic and mechanistic study

Gas‐phase pyrolysis reactions of 4(2′‐dimethylaminoethenyl)‐2‐oxo‐2H‐benzo[b]pyran‐3‐carbonitrile ( 1 ), 4(2′‐dimethylaminoethenyl)‐2‐oxo‐2H‐naphtho[1,2‐b]pyran‐3‐carbonitrile ( 2 ), 1,6‐dihydro‐4‐(2′‐dimethylaminoethenyl)‐6‐oxo‐1‐phenylpyridazine‐3,5‐dicarbonitrile ( 3 ), 2‐cyano‐5‐dimethylamino‐3‐phenyl‐2,4‐pentadienonitrile ( 4 ), 2‐cyano‐5‐dimethylamino‐3‐(2‐thienyl)‐2,4‐pentadienonitrile( 5 ), 1,2‐dihydro‐4‐(2′‐dimethylaminoethenyl)‐oxo‐quinoline‐4‐carbonitrile ( 6 ), 6‐(ethylthio)‐4‐(2′‐dimethylaminoethenyl)‐2‐phenylpyrimidine‐5‐carbonitrile ( 7 ) (Scheme 1) have been carried out. The rates of gas‐phase pyrolytic reactions of compounds 3, 4, 5, and 7 have been measured and found to correspond to unimolecular first‐order reactions. Product analyses together with kinetic data were used to outline a feasible pathway for the pyrolytic reactions of the compounds under study. © 2001 John Wiley & Sons, Inc. Heteroatom Chem 12:47–51, 2001     

Anionic polymerization of 4‐phenyl‐1‐buten‐3‐yne derivatives bearing electron‐withdrawing groups

The anionic polymerization of derivatives of 4‐phenyl‐1‐buten‐3‐yne was carried out to investigate the effect of substituents on the polymerization behavior. The polymerization of 4‐(4‐fluorophenyl)‐1‐buten‐3‐yne and 4‐(2‐fluorophenyl)‐1‐buten‐3‐yne in tetrahydrofuran at −78 °C with n‐BuLi/sparteine as an initiator gave polymers consisting of 1,2‐ and 1,4‐polymerized units in quantitative yields with ratios of 80/20 and 88/12, respectively. The molecular weights of the polymers were controlled by the ratio of the monomers to n‐BuLi, and the distribution was relatively narrow (weight‐average molecular weight/number‐average molecular weight < 1.2), supporting the living nature of the polymerization. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 1016–1023, 2001     

Synthesis of high molecular weight trans‐poly(9,9‐di‐n‐octylfluorene‐2,7‐vinylene) by the acyclic diene metathesis polymerization using molybdenum catalysts

High molecular weight trans‐poly(9,9‐di‐n‐octylfluorene‐2,7‐vinylene) was prepared under reduced pressure in the presence of a well‐defined Schrock‐type catalyst, Mo(CHCMe₂Ph)(N‐2,6‐Me₂C₆H₃)[OCMe(CF₃)₂]₂, in toluene. The effect of initial monomer concentration was found to be an important factor for preparing high molecular weight polymers with unimodal molecular weight distributions. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 2463–2470, 2001     

Synthesis and antimicrobial activity of 2,10‐dichloro‐6‐substituted‐4,8‐dinitro‐12H‐dibenzo[d,g][1,3,2]dioxaphosphocin 6‐oxides/sulfides

Novel 2,10‐dichloro‐6‐substituted‐4,8‐dinitro‐12H‐dibenzo[d,g][1,3,2]dioxaphosphocin 6‐oxides ( 4a–h ) were synthesized by reacting 5,5′‐dichloro‐3,3′‐dinitro‐2,2′‐dihydroxydiphenylmethane ( 2 ) with different aryl phosphorodichloridates ( 3a–g ) or bis(2‐chloroethyl)phosphoramidic dichloride ( 3h ) in the presence of triethylamine at 55–60°C, and the compounds 4i–l were prepared by reacting the 2,6,10‐trichloro‐4,8‐dinitro‐12H‐dibenzo[d,g][1,3,2]dioxaphosphocin 6‐sulfide ( 5 ) in situ with substituted phenols and thiophenol 5 was prepared by condensing 2 with thiophosphoryl chloride. IR, ¹H, ¹³C, ³¹P NMR, and mass spectra supported all the proposed structures. Several title compounds exhibited significant activity in the assays against the bacteria Bacillus subtilis and Escherichia coli and fungi Curvularia lunata and Aspergillus niger. © 2001 John Wiley & Sons, Inc. Heteroatom Chem 12:10–15, 2001     

Thermolysis of 3‐alkyl‐3‐methyl‐1,2‐dioxetanes: Activation parameters and chemiexcitation yields

3‐Methyl‐3‐(3‐pentyl)‐1,2‐dioxetane 1 and 3‐methyl‐3‐(2,2‐dimethyl‐1‐propyl)‐1,2‐dioxetane 2 were synthesized in low yield by the α‐bromohydroperoxide method. The activation parameters were determined by the chemiluminescence method (for 1 ΔH‡ = 25.0 ± 0.3 kcal/mol, ΔS‡ = −1.0 entropy unit (e.u.), ΔG‡ = 25.3 kcal/mol, k₁ (60°C) = 4.6 × 10⁻⁴s⁻¹; for 2 ΔH‡ = 24.2 ± 0.2 kcal/mol, ΔS‡ = −2.0 e.u., ΔG‡ = 24.9 kcal/mol, k₁ (60°C) = 9.2 × 10⁻⁴s⁻¹. Thermolysis of 1–2 produced excited carbonyl fragments (direct production of high yields of triplets relative to excited singlets) (chemiexcitation yields for 1: ϕ^T = 0.02, ϕ ≤ 0.0005; for 2: ϕ^T = 0.02, ϕ^S ≤ 0.0004). The results are discussed in relation to a diradical‐like mechanism. © 2001 John Wiley & Sons, Inc. Heteroatom Chem 12:459–462, 2001     

Thermolysis of 3‐alkyl‐3‐methyl‐1,2‐dioxetanes: activation parameters and chemiexcitation yields

3‐Methyl‐3‐(3‐pentyl)‐1,2‐dioxetane 1 and 3‐methyl‐3‐(2,2‐dimethyl‐1‐propyl)‐1,2‐dioxetane 2 were synthesized in low yield by the α‐bromohydroperoxide method. The activation parameters were determined by the chemiluminescence method (for 1 ΔH‡ = 25.0 ± 0.3 kcal/mol, ΔS‡ = −1.0 entropy unit (e.u.), ΔG‡ = 25.3 kcal/mol, k₁ (60°C) = 4.6 × 10⁻⁴s⁻¹; for 2 ΔH‡ = 24.2 ± 0.2 kcal/mol, ΔS‡ = −2.0 e.u., ΔG‡ = 24.9 kcal/mol, k₁ (60°C) = 9.2 × 10⁻⁴s⁻¹. Thermolysis of 1–2 produced excited carbonyl fragments (direct production of high yields of triplets relative to excited singlets) (chemiexcitation yields for 1: ϕ^T = 0.02, ϕ^S ≤ 0.0005; for 2: ϕ^T = 0.02, ϕ^S ≤ 0.0004). The results are discussed in relation to a diradical‐like mechanism. © 2001 John Wiley & Sons, Inc. Heteroatom Chem 12:176–179, 2001     

Synthesis and antimicrobial activity of 8‐alkylcarbamato‐16H‐dinaphtho [2,1‐d:1′,2′‐g] 1,3,2‐dioxaphosphocin 8‐oxides

A new family of phosphorus heterocycles, namely 8‐alkylcarbamato‐16H‐dinaphtho‐[2,1‐d: 1′,2′‐g] 1,3,2‐dioxaphosphocin 8‐oxides ( 4a–j ) has been obtained by reaction of bis(2‐hydroxy‐1‐naphthyl)methane ( 3 ) with a series of dichlorophosphosphinyl carbamates ( 2a–j ) in dry toluene in the presence of triethylamine at 40–45°C. The intermediates 2a–j were obtained by the addition of alcohols/thiol to isocyanatophosphonic dichloride ( 1 ) at −10°C in dry toluene. The structures of the title compounds were confirmed by the elemental analyses, IR, ¹H, ¹³C, and ³¹P NMR spectra. The FAB mass spectrum of one member of the family is discussed. These compounds were found to possess good antimicrobial activity. © 2001 John Wiley & Sons, Inc. Heteroatom Chem 12:16–20, 2001     

Synthesis of spiro[3,4‐diaryl‐4,5‐dihydroisoxazole‐5,2′‐1′,2′,3′,4‐tetrahydro‐1′‐naphthalenone]

Synthesis of a series of novel spiro[3,4‐diaryl‐4,5‐dihydroisoxazole‐5,2′‐1′,2′,3′,4′‐tetrahydro‐1′‐naphthalenone] has been described by the regioselective cycloaddition of nitrile oxides with 2‐arylmethylene‐1,2,3,4‐tetrahydro‐1‐naphthalenone. © 2001 John Wiley & Sons, Inc. Heteroatom Chem 12:463–467, 2001     

Soluble fluorinated polyimides derived from 1,4‐ (4′‐aminophenoxy)‐2‐(3′‐trifluoromethylphenyl)benzene and aromatic dianhydrides

New fluorinated aromatic polyimides were prepared from 1,4‐(4′‐aminophenoxy)‐2‐(3′‐trifluoromethylphenyl)benzene and aromatic dianhydrides via the polycondensation of one‐step high‐temperature and two‐step thermal or chemical imidization methods. Experimental results indicated that some of the polyimides were soluble both in strong dipolar solvents (N‐methyl‐2‐pyrrolidone or N,N‐dimethylacetamide) and in common organic solvents such as tetrahydrofuran, CHCl₃, and acetone. The polyimides showed exceptional thermal and thermooxidative stability and good mechanical properties. No weight loss was detected before a temperature of 520 °C in nitrogen, and the glass‐transition temperatures ranged from 208 to 251 °C. Low dielectric constants (2.55–2.71 at 1 MHz), low refractive indices, and low water absorption were also observed. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 2404–2413, 2001     

Reaction of 2‐amino‐3‐cyano‐4,5,6,7‐tetrahydrobenzo‐[b]thiophene with ethyl acetoacetate: Novel syntheses of pyridines,pyrazoles, and their fused derivatives

The reaction of 2‐amino‐3‐cyano‐4,5,6,7‐tetrahydrobenzo[b]thiophene 1 with ethyl acetoacetate 2 gave compound 3 . The reactivity of the latter product toward a variety of chemical reagents was studied to give fused thiophene derivatives of potential pharmaceutical interest. © 2001 John Wiley & Sons, Inc. Heteroatom Chem 12:518–527, 2001     

The synthesis of six‐membered P‐heterocycles with sterically demanding substituent on the phosphorus atom

The ring enlargement of 1‐(2,4,6‐trialkylphenyl)2,5‐dihydro‐1H‐phosphole oxides ( 1 ) via 6,6‐dichloro‐3‐Phosphabicyclo[3.1.0]hexanes ( 2 ) afforded the double‐bond isomers of 1,2‐dihydrophosphinine oxides ( 3 ). Catalytic hydrogenation of the isomeric 1‐(di‐tert‐butyltolyl)‐1,2‐dihydrophosphinine oxides ( 3a ) gave the diastereomers of phosphinane oxide ( 4 ), while that of the 1‐(tri‐isopropylphenyl) isomers ( 5 ) led predominantly to phospholane oxides ( 6 ) formed by ring contraction. © 2001 John Wiley & Sons, Inc. Heteroatom Chem 12:528–533, 2001     

Decomposition of model alkoxyamines in simple and polymerizing systems. I. 2,2,6,6‐tetramethylpiperidinyl‐ N‐oxyl‐based compounds

The thermal decomposition of five alkoxyamines labeled TEMPO–R, where TEMPO was 2,2,6,6‐tetramethylpiperidinyl‐N‐oxyl and R was cumyl (Cum), 2‐tert‐butoxy‐carbonyl‐2‐propyl (PEst), phenylethyl (PhEt), 1‐tert‐butoxy‐carbonylethyl (EEst), or 1‐methoxycarbonyl‐3‐methyl‐3‐phenylbutyl (Acrylate‐Cum), was studied with ¹H NMR in the absence and presence of styrene and methyl methacrylate. The major products were alkenes and the hydroxylamine 1‐hydroxy‐2,2,6,6‐tetramethyl‐ piperidine (TEMPOH), and in monomer‐containing solutions, unimeric and polymeric alkoxyamines and alkenes were also found. Furthermore, the reactions between TEMPO and the radicals EEst and PEst were studied with chemically induced dynamic nuclear polarization. In comparison with coupling, TEMPO reacted with the radicals Cum, PEst, PhEt, and EEst and their unimeric styrene adducts by disproportionation to alkenes and TEMPOH only to a minor extent (0.6–3%) but with the radical adducts to methyl methacrylate to a considerable degree (≥20%). Parallel to the radical cleavage, TEMPO–EEst (but not the other alkoxyamines or TEMPO–Acrylate‐Cum) underwent substantial nonradical decay. The consequences for TEMPO‐mediated living radical polymerizations are discussed. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3604–3621, 2001     

Phase behavior of ternary poly‐(2‐vinylpyridine)/poly‐(N‐vinyl‐2‐pyrrolidone)/bis‐(4‐hydroxyphenyl)methane blends

The phase behavior of ternary poly‐(2‐vinylpyridine) (P2VPy)/poly‐(N‐vinyl‐2‐pyrrolidone) (PVP)/bis‐(4‐hydroxyphenyl)methane (BHPM) blends was studied. Fourier transform infrared spectroscopic examinations demonstrated that BHPM interacts with P2VPy and PVP through hydrogen‐bonding interactions. The addition of a sufficiently large amount of BHPM transformed an opaque blend with two glass‐transition temperatures (T_g's) to a transparent single‐T_g blend. Scanning electron microscopic studies showed that the transparent single‐T_g blend is micro‐phase‐separated at a scale of about 30 nm. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 1815–1823, 2001     

Thermal stability of brominated poly(isobutylene‐co‐isoprene)

The thermal stability of brominated isobutylene–isoprene rubber (BIIR) was investigated through studies of the elastomer and a model compound that accurately represented the reactive functionality within the polymer. An analysis of commercial BIIR and reaction products of brominated 2,2,4,8,8‐pentamethyl‐4‐nonene (BPMN) by NMR demonstrated that bromination of isobutylene–isoprene rubber by 1,3‐dibromo‐5,5‐dimethylhydantoin yielded a kinetically favored exomethylene substitution product, 3‐bromo‐6,6‐dimethyl‐2‐(2,2‐dimethylpropyl)‐1‐heptene ( 2 ), as opposed to the more stable endo‐isomer, (E,Z)‐4‐(bromomethyl)‐2,2,8,8‐tetramethyl‐4‐nonene ( 3 ). The exposure of BIIR and the brominated model compound BPMN to vulcanization temperatures led to the isomerization of 2 to 3 at a rate strongly dependent on HBr concentration. The elimination of HBr from these allylic bromides to produce exo‐ and endo‐conjugated dienes proceeded concurrently with isomerization, and the kinetics of these processes could be rationalized on the basis of a polar reaction mechanism. The product distributions obtained from both the model system and BIIR were consistent, thereby justifying an extension of the model compound approach to an analysis of BIIR vulcanization chemistry. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 2019–2026, 2001     

Thiofenchone s‐methylide and its spiro‐1,3,4‐thiadiazoline precursor

Spiro[fenchane‐2,2′‐(1,3,4)‐thiadiazoline] ( 6 ), prepared from thiofenchone and diazomethane, extrudes N₂ (t_1/2 22 min, 46°C, toluene) and furnishes the S‐methylide 7 which, in turn, closes the thiirane ring or else is intercepted by 1,3‐cycloadditions to dipolarophiles (tetracyanoethylene, maleic anhydride, N‐methyl‐1,2,4‐triazoline‐3,5‐dione, aromatic thioketones). When thiocarbonyl S‐methylide 7 is set free in methanol, fenchone S,O‐dimethylacetal is formed as an HX adduct. Catalysis by acetic acid converts 7 to 1‐(methylthio)‐α‐fenchene ( 25 ) by way of a Wagner‐Meerwein rearrangement. The addition of diazomethane to thiocampher leads, via thiadiazoline 12 , to thiocamphor S‐methylide; the latter undergoes a 1,4‐H shift, thus affording 2‐methylthio‐2‐bornene ( 11 ). © 2001 John Wiley & Sons, Inc. Heteroatom Chem 12:136–145, 2001