Synthese von (5,10)-(7,8)-Bisepoxiden aus α- und β-4-Phenyl-1,2,4-triazolin-3,5-dion-Addukten von Vitamin D3 und Röntgenstrukturanalyse eines der Benzoylderivate

Oxidation of the α- and β-4-phenyl-1,2,4-triazolin-3,5-dione adducts of vitamin D₃ (2 and1) withMCPBA yields two diastereomeric mixtures of the (5,10)-(7,8)-dioxiranes3 a,3 b,3 c and4 a,4 b respectively. The corresponding benzoates5 a,5 b,6 a and6 b were prepared and the X-ray crystal structure of5 b was determined. This analysis proved5 b to be the (5R, 1 OS)-(7R, 8R)-dioxirane of the β-resp. (6S)-4-phenyl-1,2,4-triazolin-3,5-dione adduct1 of vitamin D₃.     

Synthese von 1-substituierten 4-Amino-2(1H)-pyridinthionen durchDimroth-Umlagerung aus 2,4-Diaminothiopyranyliumhalogeniden

4-Amino-2-alkylimino-2H-thiopyranes (5) and 4-amino-2-alkylaminothiopyranylium halogenides (4) resp. on heating in refluxingDMFA are rearranged in the presence of Na-ethylate to 1-alkyl-4-aminodihydro-2(1H)-pyridinethiones (2). Also 2-methylthiothiopyranylidenammonium iodides (6) and 2-methylthio-4H-thiopyrane-4-one (7) can be transformed into 1-substituted 2(1 H)-pyridinethiones (2) by heating in prim. amines. On treatment with alkali. 4-dimethylaminothiopyranylium iodide (4 a) is transformed into its base5 a and hydrolyzed to8. 5a and8 are rearranged to the pyridinethiones2 a and the tautomers9 A,B. The structure of the rearranged pyridinethiones2 was proved by the1-phenylderivate2 a. Thus 4-methyl-3-penten-2-on reacts with phenylthiourea via the phenylimino-1,3-thiazine (14) to give 3-phenyl-2(1H)pyridinethione (15).15 is transformed by themethylpyrimidine-pyridine-rearrangement to the 1-phenylpyridinethione2 a. The mechanism of theDimroth-reaction of 2-alkylimino-2H-thiopyranes (5) and the stereochemistry of the1-benzyl-6-phenyl-2(1H)-pyridinethiones2 are discussed.     

Chemie des 5,7-Dihydroxy-2H-thiopyrano[2,3-b]pyridin-4(3H)-ons

Hydrolysis of the 4-alkyliminothiopyrano[2,3-b]pyridinedioles (5) and 4-alkylaminothiopyrano[2,3-b]pyridones (6) resp. with 10% NaOH gives 5,7-dihydroxy-2H-thiopyrano[2,3-b]pyridine-4(3H)-one (7).7 can be obtained in better yield by reaction of 4-dimethylamino-2(1H)-pyridinethione (8) with bistrichlorphenylethylamlonate (2). Aminolysis of7 affords the two isomeric products5 and6. On treatment with hydrazines,7 reacts only to 4-hydrazonoderivatives5. By heating in bromobenzene5d is cyclisized to 1H-5,1,2,6-thiatriaza-acenaphthylen-7-ol (11). On methylation with methyljodide5,6 and7 furnish the 7-methoxyproducts13,14 and12. By heating in 20% NaOH7 is transformed into the 2-thioxo-3-pyridylmethylketone16 A and its tautomer, 2-mercapto-3-pyridylmethylketone16 B. The structures of5,6 and7 are discussed.     

Carbon-nitrogen bond formation in the reaction of the reaction of diphenyl diazomethane Ph2 CN2 with diiron-carbene complexes (Fe2(CO)7x03BD;-C(R)C(NEt2)x03BD;-C(R)C(NEtx03BC;-C(R)C(NEt2)N(NCPh2)x03BC;-C(R)C(NEtx03BC;-C(R)C(NEt2)NN(CPh2)x03BC;-C(R)C(NEt)]

The diiron ynamine complex [Fe₂(CO)₇{μ-CR)C(NEt₂)}] (1:R=Me,2:R = C₃H₅.3:R=SiMe₃.4:R = Ph) reacts at room temperature with diphenyldiazomethane Ph₂CN₂, in hexane to yield complexes [Fe₂(CO)₆{C(R)C(NEt₂)N (NCPh₂)] (5a:R=Me,6a:R=C₃H₅.7a R=SiMe₃.8a:R=Ph) resulting from the insertion of the terminal nitrogen atom into the Fe=C carbene bond. Insertion the second nitrogen atom and formation of compounds [Fe₂(CO)₆zμ-C(R)C(NEt₂)NN(CPh₂)}] (5b:R=Me,6b:R=C₃H₅,7b:R=SiMe₃,8b:R=Ph) is observed when compounds5a-5a are treated in refluxing hexane. Transformation of compoundsa tob is also obtained at room temperature within a few days. All compounds were identified by their¹H NMR spectra. Compounds6a, 7a, 8a, and8b were characterized by single crystal X-ray diffraction analyses. Crystal data: for6a: space group = P2₁/n,a=12.853(1) A,b=24.800(7) A,c=8.947(6) A,β=99.29(3)°,Z=4, 2227 rellectionsR=0,038; for7a: space group=Pl,a=ll.483(4) A,b=14.975(4) A,c = 17.890(8) A,α = 82.80(3)°,β=94.29(7)°,γ=85.42(2),Z = 4, 5888 reflectionR = 0.035: for8a: space group = Pcab.a = 31.023(8) A.b=20.137(1) A.c=9.686(2) A.Z=8. 1651 reflections,R=0.071; for8b: space group=P2₁/n,a=21.459(4),b=10,100(3) A,c=28,439(8) A,ß=103.86(4)°,Z=8. 2431 reflections.R=0.057.     

Biocatalytic desymmetrization of 3-substituted glutaronitriles by nitrilases. A convenient chemoenzymatic access to optically active (S)-Pregabalin and (R)-Baclofen

<正>1 General procedure for the preparation of 3-substituted glutaronitriles To a 100 mL flask containing aldehyde(30 mmol) and cyanoacetic acid(10.20 g, 120 mmol) was added 4-methylpiperidine(0.4 mL) and 23 mL N-methylmorpholine. The reaction mixture was warmed to mild reflux for 24 h and then cooled to room temperature and concentrated on a rotary evaporator. The resulting mixture was dissolved in 100     

Zur Kenntnis der Reaktionsfähigkeit von 4-Hydrazino-2,5-di-tert.-butyl-2-methyl-2H-imidazol

4-Hydrazino-2.5-di-tert.-Butyl-2-methyl-2H-imidazole (1) reacts with aldehydes and ketones to give condensation products (2 a-1). The reaction of1 with acyl chlorides and dicarboxylic acid chlorides gives rise to the corresponding 4-acylhydrazino-2H-imidazoles (3 a, b) and dicarboxylic-bis(imidazole-4-yl)-hydrazides (4 a-c) resp. Heating1 with acetyl bromide, ethyl orthoformate and 3-bromo-4-methyl-2-pentanone affords new condensedring systems5 a, b and7, resp.     

Über cyclische Guanidin—Mesityloxid- und Guanidin—Phoron-Kondensate

The basic product synthesized byTraube andSchwarz from mesityl oxide and guanidine has not been 4.4.6-trimethyl-4.5-dihydro-2-pyrimidinamine (1), but a mixture containing the 4.4.6-trimethyl-3.4-dihydro-2(1H)-pyrimidinimine (resp. an isomeric pyrimidinamine)2 a (resp.2 b, 2 c) and the dimeric 4.4′-methylenedi[2(1H)-pyrimidinimine] (resp. an isomeric methylenedipyrimidinamine)3 a (resp.3 b, 2 c) and the dimerisation reaction were studied in a series of experiments. The product of the reaction of guanidine and phorone is not the guanidinopropylpyrimidine8 ⁴, but the 4.4′-spirobi[2(1H)-pyrimidinimine] (resp. a spirobipyrimidinamine)11 a (resp.11 b, 11 c). No determination was possible on the basis of NMR whether the condensation products of guanidine—in solutions ofDMSO-d₆—are pyrimidinimines (2 a, 3 a, 11 a) or pyrimidinamines (2 b resp.2 c, 3 b resp.3 c, 11 b resp.11 c) or mixtures of the isomeric compounds. The NMR-and mass spectra of2 a (resp.2 b, 2 c),3 a (resp.3 b, 3 c),11 a (resp.11 b, 11 c) and their derivates are discussed.     

Zur Chemie der 5-Alkylamino-4H-thiopyrano[2,3-b]pyridin-4-one

4-Alkylaminopyridinethiones · HCl (1 · HCl) react with bis-trichlorethylmalonate (3) predominantly to 5-alkylamino-4H-thiopyrano [2,3-b]pyridine-4-ones (6). With alcohols in the presence of acids at 25°C6 undergoes an alcoholysis to the corresponding alkyl-3-(2-thioxo-3-pyridyl)propionates (9). On heating in dilute alkali6 is hydrolysed via 4-alkylamino-2-thioxopyridyl-propylketones (11) to the tautomers, 4-hydroxy-2-thioxopyridylpropylketone (12 A) and 2-thioxo-3-(1-hydroxybutenyl)-4-piperidon (12 B), resp. On refluxing with alkali the ethyl-pyridylpropionate9 a is cyclisized to the 1-alkyl-1,6-naphthyridine-2(1H)-one (4 a), but boiling in ethanolic acid hydrolyses9 a via the pyridylpropionic acid10 to 4-alkyl-aminopyridylpropylketone (11 a). The latter can be transformed via the tautomers12 A,B and 2-methylthio-3-pyridylpropylketone (13) to the 4-hydroxy-3-butyrylpyridone (14 A) and its tautomer, 3-(1-hydroxy-butenyl)-piperidine-2,4-diones (14 B) resp. The structure of14 A,B is established by reaction of 4-isopropylamino-2(1H)-pyridone (2) with butanoylchloride to the 4-isopropylamino-3-butyrypyridone (15) and hydrolysis of15 to the tautomers14 A,B.     

Chinolizine und Indolizine,XIII. Acyl-2-hydroxy-4-chinolizinone

The reaction of 2-picolylketones (1 a, b) with reactive trichlorophenyl malonates (2 a–f) leads to 1-acyl-2-hydroxy-4-quinoliziones (3 a–i) which can be easily deacylated by boiling hydrochloric acid yielding 4-quinolizinones4 a–f. The 3-acetyl-2-hydroxy-4-quinolizinones6 and8 are obtained byKlosa-Ziegler acylation of4 a and7, respectively. The reaction of the acetyl compound3 a with acetic anhydride yields the 2-pyrone derivative9, whereas the propionyl derivative3 g yields the 4-pyrone10 under the same conditions. Nitration of3 e does not give the 1-nitro derivative12 but rather the 1,3-dinitro compound11.     

Synthesis and characterization of 2-alkyl -5-{4-[(3-nitrophenyl-5-isoxazolyl)methoxy]phenyl}-2H-tetrazoles

Heteroaryl substituted analogs of antirhnoviral (A), was prepared by a convergent approach. 3-Nitrophenyl-5- bromooromethylisoxazoles 5a–b were synthesized by [3+2] cycloaddition of 3-(benzoyloxy)-propyne 2 to in situ generated arylnitrile oxides followed by deprotection of cycloadducts 3a–b and bromination of the resulting alcohols 4a–b. Coupling of 3- nitrophenyl-5-bromooromethylisoxazoles (5a–b) with 4-[5-(2-alkyl-2H-tetrazolyl)]phenols (6a–d) in N-methylpyrrolidinone under mild conditions afforded a new series of 2-alkyl-5-{4-[1-(3-nitrophenyl-5-isoxazolyl)methyloxy]phenylr}-2H-tetrazoles (7a–h) in high yields. The structures of the synthesized compounds were confirmed by their ¹H NMR, Mass spectral, and Elemental Analysis data.     

Synthesis, reactions and antineoplastic activity of 3-(2-oxo-2H-chromen-3-yl)-2-oxo-2H,5H-pyrano[3,2-c]chromene derivatives

The key 3-(2-oxo-2H-chromen-3-yl)-2-oxo-2H,5H-pyrano[3,2-c]chromen-5-yl acetates 3 were synthesized in high yields by cyclocondensation of 4-oxo-4H-chromen-3-carbaldehydes 1 with coumarin-3-acetic acids 2 under mild conditions. The reaction pathway involves aldol condensation and subsequent intramolecular lactonization to afford 2-oxo-2H,5H-pyrano[3,2-c]chromene skeleton 3. Further treatment of acetates 3 with alcohols, water or nitrogen containing compounds led to 5-alkoxy-, 5-hydroxy- or 5-acylamino-2H,5H-pyrano[3,2-c]chromen-2-ones 4-6 via nucleophilic substitution of acetyloxy group at C-5. Acetates and hydroxyl derivatives 3 and 5 undergo facile rearrangement in an acid medium yielding 5-hydroxypyrano[2,3-b]chromen-2(10aH)-ones 7. Twelve prepared compounds were evaluated on their antineoplastic activities on 60 human tumour cell line panels in NCI USA. The obtained biological results confirmed that 3-(2-oxo-2H-chromen-3-yl)-2H,5H-pyrano[3,2-c]chromen-2-one represents a new leading skeleton suitable for further antitumour activity study.     

Thiourea-halide lattices. Part 1. Crystal structures of (n-C4H9)4N+F−·3(NH2)2CS, (n-C4H9)3(CH3) N+X−·2(NH2)2CS (X = Cl,Br), and (n-C3H7)4N+I−·(NH2)2CS

The title complexes (1, X = F;2, X = C 1; 3, X = Br and isomorphous with2; 4, X = I) have been prepared and characterized by X-ray crystallography. Crystal data, MoKα radiation:1, space groupCc,Z =4,a = 12.017(3),b = 14.263(5),c = 17.210(7) Å,β = 103.06(2)°, andR _F =0.053 for 2044 observed data;2, space groupCc,Z = 4,a = 12.817(3),b = 11.072(2),c = 16.781(5) Å,β =90.74(2)°,R _F = 0.044 for 2249 data;3,a = 12.873(4),b = 11. 119(2),c = 16.957(2) Å,β = 89.11(2)°,R _F = 0.049 for 2059 data;4, space groupP2₁/n,Z = 4,a = 8.858(2),b = 14.358(3),c = 15.379(3) Å,β = 93.88(1)°,R _F = 0.068 for 3119 data. In all four structures each thiourea molecule interacts with adjacent thiourea molecules via N-H ... S hydrogen bonds to give a ribbon-like arrangement, and also forms a pair of ‘chelating’ N-H ... X hydrogen bonds with a halide ion, resulting in an anionic framework (in1–3) or composite ribbon (in4) as a component in the crystal packing. The measured ranges of N... X distances are: 2.819(5)-2.994(7) Å for1, 3.252(3)-3.291(3)Å for 2, 3.353(6)-3.459(6)Å for3, and 3.564(5)-3.680(5) Å for 4.     

Triazolo[4′,3′:4,5] [1,3,4]thiadiazolo[2,3-b]quinazolin-6-one

3-Methyl-6H-[1,2,4]triazolo[4′,3′: 4,5] [1,3,4]thiadiazolo[2,3-b]quinazolin-6-one (6) has been synthesized by the condensation of isatoic anhydride (1) with 4-amino-5-mercapto-3-methyl-[1,2,4]triazole (2) and final cyclisation of the intermediate3 with POCl₃ and PCl₃. Alternatively6 could also be synthesized by the condensation of 3-amino-2-mercapto-3H-quinazolin-4-one (7) withN-carbethoxy hydrazine in presence of hydrochloric acid and final cyclisation of the intermediate8 with acetic acid. The structures have been confirmed on the basis of IR, PMR and analytical results.     

Zur Kenntnis der Substitutionsprodukte der (2H)-Imidazol-4(3H)-thione und 2H-Imidazol-4(3H)-one

2H-Imidazole-4(3H)-thiones (a), available from methyl alkyl and methyl aryl ketones with sulfur and ammonia, react via their corresponding N-sodium compounds or in presence of tert. amines with alkyl and aryl carboxylic acid chlorides to give the corresponding intensely coloured (orange to violett) cryst. 3-acyl-2H-imidazole-4(3H)-thiones4 a-q and6–26. With dicarboxylic acid dichlorides the colourless cryst. N,N′-diacyl-bis-3-imidazoline-5-thiones5 a-d and27–32 are obtained. With carbamic acid chlorides and chloroformic acid esters the corresponding urea (33–35) and urethane derivatives36, 37 are formed. In an analogous way 2H-imidazol-4(3H)-ones react with acid chlorides to 3-acyl-2-imidazol-4(3H)-ones (44–50), which can also be obtained by treating the corresponding 3-acyl-2H-imidazole-4(3H)-thione with KMnO₄.     

Guest inclusion in cyclic imides containing flexible tethers

Guest inclusion properties of two cyclic imides which have carboxylic acids connected through flexible tether, namely, 4-(1,3-dioxo-1,3-dihydro-isoindol-2-ylmethyl)-cyclohexanecarboxylic acid (1) and 4-(1,3-dioxo-1H,3H-benzo[de]isoquinolin-2-ylmethyl)-cyclohexanecarboxylic acid (2) are studied. The crystals of host 1 containing one molecule of 1, the crystals of 4,4′-bipyridine (bpy) cocrystal of 1 containing one molecule of 1 and half molecule of bpy (1a), the crystals of 1,4-dioxane solvate of 1 containing two molecule of 1 and one and half molecule of 1,4-dioxane (1b) and the crystals of quinoline solvate of 1 containing one molecule of 1 and one molecule of quinoline (1c) in their crystallographic asymmetric units are investigated. Intermolecular hydrogen bonded two dimensional (2D) sheet structure of 1 and 3D channel network of 1b are comprised of cyclic R ₂ ² (8) hydrogen bond motifs; whereas cleavage of dimeric carboxylic acid R ₂ ² (8) motifs occurs in the structures of 1a and 1c in which 3D host–guest networks are comprised of discrete O–H···N and cyclic R ₂ ² (7) interactions, respectively. Various types of weak interactions between the two symmetry nonequivalent host molecule are found to be responsible for the formation of channels (14 × 11 Å) filled by guest 1,4-dioxane molecules in the crystal lattice of 1b. Two different solvates of 2 containing one molecule of 2 with a water molecule (2a) and one molecule of 2 with a quinoline molecule (2b) in their crystallographic asymmetric units, respectively, are also crystallized in different space groups. The quinoline molecules are held with host molecules by discrete O–H···N and C–H···O interactions and reside inside the voids formed by 3D repeated hexameric assemblies of host molecules in the crystal lattice of 2b.     

Synthese von Thiazolo[3,2−a]thieno[2,3−d]pyrimidin-Derivaten

Derivatives of 5H-thiazolo[3.2?a]thieno[2.3?d]pyrimidine(A), 5H-[1]benzothieno[2.3?d]thiazolo[3.2?a]pyrimidine (B), 4H-thiazolo[3.2?a]thieno[3.2?e]pyrimidine (C) and 5H-[1]benzo-thieno[3.2?e]thiazolo[3.2?a]pyrimidine (D) were synthesized by various methods. Similar reactions are leading to derivatives of thieno[2′.3′∶4.5]pyrimido[2.1?b][1.3]thiazine (E) and [1]benzothieno[2′.3′∶4.5]pyrimido[2.1?b][1.3]thiazine (F).C, D, E, andF are new heterocyclic ring systems. Detailed papers will appear soon.     

Über substituierte 2-Amino-3,4,5,6-tetrahydro-1H-pyrimidinium-und 1,2,3,4,6,7,8,9-Octahydropyrimido-[1,2—a]pyrimidiniumchloride

Crotonaldehyde resp. cinnamaldehyde react with guanidiniumchloride to give 2-amino-6-guanidinio-4-methyl-3.4.5.6-tetrahydro-1H-pyrimidiniumdichloride (4 a) resp. 6-hydroxy-4-phenylpyrimidiniumchloride3 b and the 4.6-dihydroxy-2.8-dimethyl (resp. 2.8-diphenyl)octahydropyrimido[1.2?a]pyrimidiniumchlorides6 a and6 b, resp. Action of 2.4-(or 2.6-)xylenol on4 a resp.3 b yields 2-amino-6-[2(or 4)-hydroxy-3.5-dimethylphenyl]-4-methyl-(resp. 4-phenyl)-3.4.5.6-tetrahydro-1H-pyrimidiniumchlorides (8 a resp.8 b or9 a resp.9 b), which are transformed to the zwitterionic compounds10 a–11 b by aqu. NaOH.6 a reacts with 2.4-xylenol to give the triazaoxabenzanthraceniumchlorid12 a·HCl (prove for the structure given for6 a). The chemical properties and the NMR-, UV-, mass- and IR-spectra of the compounds are discussed.     

Helix-sense-selective radical polymerization of bulky styrenic monomers: chiral induction and liquid crystallinity

Eight chiral vinylterphenyl monomers,(+)-2,5-bis{4′-[(S)-1″-methylpropyloxy]phenyl}styrene(Ia),(+)-2,5-bis{4′-[(S)-2″-methylbutyloxy]phenyl}styrene(Ib),(+)-2,5-bis{4′-[(S)-3″-methylpentyloxy]phenyl}styrene(Ic),(+)-2,5-bis{4′-[(S)-4″-methylhexyloxy]phenyl}styrene(Id),(?)-2,5-bis{4′-[(R)-1″-methylpropyloxy]phenyl}styrene(Ie),(+)-2-{4′-[(S)-1″-methylpropyloxy]phenyl}-5-{4′-[(R)-1″-methylpropyloxy]phenyl}styrene(IIa),(?)-2-{4′-[(R)-1″-methylpropyloxy]phenyl}-5-{4′-[(S)-1″-methylpropyloxy]phenyl}styrene(IIb),and(+)-2-{4′-[(S)-2′′-methylbutyloxy]phenyl}-5-{4′-[(S)-1″-methylpropyloxy]phenyl}styrene(III),were synthesized and radically polymerized.These molecules were designed to further understand long-range chirality transfer in radical polymerization and to possibly tune the chiroptical properties of the polymers by varying the spatial configuration,position,and various combination of the stereogenic centers at the ends of p-terphenyl pendants.The resultant polymers adopted helical conformations with a predominant screw sense.When the stereogenic centers ran away from the terphenyl group as in Ib?d,the corresponding polymers changed the direction of optical rotation in an alternative way and showed no obvious stereomutation upon annealing in tetrahydrofuran.The two stereogenic centers of IIa,IIb,and III acted concertedly in chiral induction,whereas those of Ia and Ie played a counteractive role.The five polymers derived from Ia,Ie,IIa,IIb,and III underwent stereomutation when annealed in tetrahydrofuran.The polymers PIa?e had good thermal stability and high glass transition temperatures(Tgs).They generated liquid crystalline phases at above Tgs that could be kept upon cooling,with the exception of PIe.This result was consistent with the extended helical structures.     

Crystal Structures of Hydrochlorides of 2,3-Pentamethylene-3, 4-dihydroquinazolin-4-one

The crystal structures of hydrate (1) and anhydrate (2) forms of 2,3-pentamethylene-3,4-dihydroquinazolin-4-one hydrochloride have been determined by X-ray structure analysis. Crystal data of 1 are 2(C₁₃H₁₄N₂O)*3(HCl)*4.5 (H₂O), triclinic P?1, Z=2, a=8.004(5), b=13.129(7), c=15.725(7) Å, α=106.45(4), β=92.61(4), γ=97.98(5), R=0.0652 and 2 are C₁₃H₁₄N₂O*HCl, monoclinic C2/c, Z=8, a=21.360(4), b=5.954(1), c=21.263(4), β=117.89(3), R=0.0556. The crystal of the hydrate form 1is unstable. This form collapses easily with evaporation of H₂O and part of HCl molecules from crystals. By recrystallizing destroyed form has been obtained stable crystal form 2.     

Synthesis of tricyclic isoindoles and thiazolo[3,2-c][1,3]benzoxazines

The thermolysis of (3R,9bS)-5-oxo-2,3,5,9b-tetrahydrothiazolo[2,3-a]isoindole-3-carboxylic acids in Ac₂O led to novel 3-methylene-2,5-dioxo-3H,9bH-oxazolo[2,3-a]isoindoles and chiral (9bS)-5-oxo-2,3,5,9b-tetrahydrothiazolo[2,3-a]isoindoles were obtained on FVP. Starting from l-cysteine methyl ester (3R,10bR)-5-oxo-2,3-dihydro-10bH-[1.3]thiazolo[3,2-c][1,3]benzoxazines were obtained as single stereoisomers. The thermolysis of (3R,10bR)-5-oxo-2,3-dihydro-10bH-[1.3]thiazolo[3,2-c][1,3]benzoxazine-3-carboxylic acid in Ac₂O gave 5-acetyl-2-phenyl-2,3-dihydrothiazole. The structures of methyl (3R,9bS)-5-oxo-2,3,5,9b-tetrahydrothiazolo[2,3-a]isoindole-3-carboxylate 1a and methyl (2R,4R)-N-chlorocarbonyl-2-(2-hydroxyphenyl)thiazolidine-4-carboxylate 9 were determined by X-ray crystallography.