2-[3-(Trifluoromethyl)phenyl]furo[3,2-b]pyrroles: synthesis and reactions

The synthesis and reactions of methyl 2-[3-(trifluoromethyl)phenyl]-4H-furo[3,2-b]pyrrole-5-carboxylate (1a) are described. Upon reaction with methyl iodide, benzyl chloride, or acetic anhydride, this compound gave N-substituted products 1b-d. By hydrolysis of compounds 1a-c, the corresponding acids 2a-c were formed, or by reaction with hydrazine-hydrate, the corresponding carbohydrazides 3a-c were formed. By heating 2-[3-(trifluoromethyl)phenly]-4H-furo[3,2-b]pyrrole-5-carboxylic acid (2a) in acetic anhydride, 4-acetyl-2-[3-(trifluoromethyl)phenyl]furo[3,2-b]pyrrole (4) was formed. By hydrolysis of 4, 2-[3-(trifluoromethyl)phenyl]-4H-furo[3,2-b]pyrrole (5a) was formed, and reactions with methyl iodide or benzyl chloride gave N-substituted products 5b-c. The reaction of 4 with dimethyl butynedioate gave substituted benzo[b]furan 6. Compound 3a reacted with triethyl orthoesters giving 7a-c, which afforded with phosphorus (V) sulphide the corresponding thiones 8a-c. The thiones 8a-c reacted with hydrazine hydrate to form hydrazine derivatives 9a-c. The reaction of triethyl orthoformiate with compounds 9a-c led to furo[2′,3′: 4,5]pyrrolo[1,2-d][1,2,4]triazolo[3,4-f][1,2,4]triazines 10a-c. Hydrazones 11a-c were formed from 3a-c and 5-[3-(trifluoromethyl)phenyl]furan-2-carboxaldehyde. The effect of microwave irradiation on some condensation reactions was compared with “classical” conditions. The results showed that microwave irradiation shortens the reaction time while affording comparable yields.     

Reactivity of 4-bromomethylquinoline derivatives towards glycine and thioglycolic acid. A new ring system

Condensation of 4-bromomethylquinoline derivatives1 a-1 c with glycine and thioglycolic acid gave the corresponding quinolylmethylglycine and quinolylmethylthioacetic acid derivatives2 a-2 c and2 d-2 f, respectively. Cyclization of2 a-2 f was affected either by polyphosphoric acid or concentrated sulphuric acid to give3 a-3 f. Chlorination of2 a-2 f and3 a-3 f were also accomplished.

---

Die Reaktivität von 4-Brommethylchinolin-Derivaten gegenüber Glycin und Thioglycolsäure. Ein neues Ringsystem

Zusammenfassung Die Reaktion von 4-Brommethylchinolin-Derivaten1 a-c mit Glycin und Thioglycolsäure gab die entsprechenden Kondensationsprodukte2 a-c und2d-f.2 a-f konnten mit Polyphosphorsäure bzw. mit konzentrierter Schwefelsäure zu Benzo[c]-2,6-naphthyridinen3 a-f zyklisiert werden.2 a-f und3 a-f waren einer Chlorierung (POCl₃) zugängig.

     

Synthesis of 4-thia analogues of isoquinoline alkaloids

Summary (±)-4-Thiacarnegin (3) was synthesized by reaction of 6,7-dimethoxy-3-methyl-2H-1,3-benzothiazinium iodide (2) with methyl magnesium iodide, thereby opening a new synthetic route to 4-substituted dihydro-2H-1,3-benzothiazines. Compound3 was also obtained by reduction of 6,7-dimethoxy-3,4-dimethyl-2H-1,3-benzothiazinium iodide (5). In a similar way, reduction of the quaternary salts9 a–c afforded the (±)-4-thia analogues of cryptostilin-I, -II and -III (10 a–c). The isomers of the former compounds (12 a–c) were also synthesized by reduction of the 4H-1,3-benzothiazinium salts11 a–c.

---

Synthese von 4-Thiaanalogen von Alkaloiden mit Isochinolingerüst

Zusammenfassung Aus 6,7-Dimethoxy-3-methyl-2H-1,3-benzothiaziniumjodid (2) wurde mit Methylmagnesiumjodid (±)-Thiacarnegin (3) dargestellt. Diese Reaktion bietet ein neues Verfahren für die Synthese von 4-substituierten Dihydro-2H-1,3-benzothiazinen.3 wurde auch durch Reduktion von 6,7-Dimethoxy-3,4-dimethyl-2H-1,3-benzothiaziniumjodid (5) erhalten. Die Reduktion der quartären Ammoniumsalze9 a–c ergab ebenfalls die Cryptostillin I-, II-, III-(±)-4-thiaanalogen Verbindungen (10 a–c). Reduktion der 4H-1,3-Benzothiazinium-Salze11 a–c lieferte die entsprechenden Isomeren12 a–c der obengenannten Verbindungen.

     

Fermi resonance in substitutedZ-3-methylene phthalides

Summary The absorption bands of the C=O Stretching vibrations of a series of thirty-nine substitutedZ-3-methylene phthalides (1a-s, 2a-h, 3a-f, 4a-c, and5a-c) were measured in CHCl₃ and CCl₄. The two-levelFermi resonance effect on the infrared spectra of the above compounds was investigated after deconvolution and band separation. The wave numbers of the unperturbed fundamental C=O stretching vibrations exhibit excellent linear correlations withHammet's constants of substituents and¹³C NMR chemical shifts of the C=O group.

---

Fermi-Resonanz in substituiertenZ-3-Methylenphthaliden

Zusammenfassung Die Absorptionsbanden der C=O-Streckschwingung von 39 substituiertenZ-3-Methylenphthaliden (1a-s, 2a-h, 3a-f, 4a-c und5a-c) wurden in CHCl₃ und CCl₄ vermessen. Durch Dekonvolution und Bandentrennung konnte der EinflußFermi-Resonanz auf die Infrarotspektren der obengenannten Verbindungen untersucht werden. Die Wellenzahlen der ungestörten C=O-Streckschwingungen ergeben ausgezeichnete lineare Korrelationen mit denHammetschen Substituentenkonstanten und den¹³C-NMR-Verschiebungen der Carbonylgruppe.

     

Transformations of pyridine and deuteropyridine under the action of trimethallylborane and alcohols. Synthesis oftrans- andcis-2,6-dimethallyl-1,2,3,6-tetrahydropyridines and theirN-derivatives

Reductivetrans-2,6-dimethallylation of pyridine and deuteropyridine with trimethallylborane in the presence of alcohols proceeds at room temperature,i.e., under substantially milder conditions than the analogous reaction with the participation of triallylborane.trans-2,6-Di(2-methylallyl)-1,2,3,6-tetrahydropyridine (3) was obtained in a yield of 87%. When heated with trimethallylborane (130–135°C, 2.5 h), compound3 underwent isomerization tocis-2,6-di(2-methylallyl)-1,2,3,6-tetrahydropyridine (4). Hydrogenation oftrans- (3) andcis-isomers (4) yieldedtrans- andcis-2,6-diisobutylpiperidines, respectively. The heterocycles obtained wereN-functionalized by reactions with MeI, PhCH₂Cl, ethylene oxide, and perfluoropropyloxirane. The stereochemistry of thecis- andtrans-isomers (3 and4) was established based on the NMR spectra of theirN,N-dimethyl salts and the products of the reaction with ethylene oxide.trans-2,6-Dimethallyl-2,3,4,5,6-pentadeutero-1,2,3,6-tetrahydropyridine and a number of its derivatives were prepared from the complex of trimethallylborane with C₅D₅N. A probable mechanism of the reductivetrans-2,6-diallylation of pyridines with allylboranes in the presence of alcohols is discussed. This article is dedicated to Prof. W. Siebert (Heidelberg) on the occasion of his 60th birthday. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1361–1370, July, 1997.     

Reductivetrans-2,6-diallylation of pyridines with allylboranes. Synthesis oftrans- andcis-2,6-diallyl-1,2,5,6-tetrahydropyridines and their deuterated derivatives

The reductivetrans-2,6-diallylation of pyridines with triallyl- and allyl(dialkyl)boranes has been discovered. Heating (40–100 °C) of pyridine, deuteropyridine, or 3-bromopyridine complexes with triallylborane in the presence of alcohols (ROH or CH₃OD), water, or Et₂NH results in the respectivetrans-2,6-diaIlyl-1,2,5,6-tetrahydropyridines (2,3,22, or25) in 20–97 % yields. A preparative method for the isomerization oftrans-2,6-diallyl compounds2 and25 into the respectivecis-isomers4 and28 by heating them with triallyl- or allyl(dialkyl)boranes (125–150 °C) has been suggested. The hydrogenation oftrans- orcis-2,6-diallyl-1,2,5,6-tetrahydropyridines gavetrans- orcis-2,6-dipropylpiperidines, respectively. Thecis- andtrans-configurations of compounds2 and4 were established by analyzing the NMR spectra ofN-benzyl (7 and13) andN,N-dimethyl (6 and 14) derivatives of piperidine derivatives5 and8. A possible mechanism for the reductive diallylation of pyridines has been discussed.Translated fromIzyestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 693–704, April, 1994.This study was financially supported by the Russian Foundation for Basic Research (Project 93-03-18193).     

A study of the Claisen rearrangement of 7-(3-phenyl-2-propenyloxy)-3-phenyl-(4H)-1-benzopyran-4-one derivatives

Summary The Claisen rearrangement of 7-(3-phenyl-2-propenyloxy)-3-phenyl-(4H)-1-benzopyran-4-one (2 a) gave 7-hydroxy-8-(1-phenyl-2-propenyl)-3-phenyl-(4H)-1-benzopyran-4-one (3 a) and 2,3-dihydro-2,6-diphenyl-3-methyl-(7H)furo[2,3-h]-1-benzopyran-7-one (7 a). 2-Methyl-7-(3-phenyl-2-propenyloxy)-3-phenyl-(4H)-1-benzopyran-4-one (2 b) afforded4 b and7 b. 8-Methyl-7-(3-phenyl-2-propenyloxy)-3-phenyl-(4H)-1-benzopyran-4-one (12) gave only the alkali soluble product 7-hydroxy-8-methyl-6-(1-phenyl-2-propenyl)-3-phenyl-(4H)-1-benzopyran-4-one (13).3 a,4 b, and13 were further cyclized in acidic medium to9 a,10 b, and14 followed by dehydrogenation.This paper is dedicated to Dr. F. M. Dean, Department of Organic Chemistry, Robert Robinson Laboratories, University of Liverpool, Liverpool, U. K., on his retirement     

Synthesis and Stereochemistry of (1S,3S,4S,7R11R)-3-(4-Nitrophenyl)-11-aza-2,6-dioxatricyclo[5,3,1,04,11]undecane

The reaction of (1S,2S)-2-amino-1-(4-nitrophenyl)-1,3-propanediol with glutaraldehyde has been studied. It has been established on the basis of AM1 and PM3 calculations and ¹H NMR spectra recorded in the presence of the shift reagent Eu(fod)₃ that (1S,3S,4S,7R,11R)-3-(4-nitrophenyl)-11-aza-2,6-dioxatricyclo[5,3,1,0^4,11]undecane is formed as the result of the reaction.     

三有机锡（4R）-3-[[（2S）-5-氧-2-吡咯烷基]羰基]-4-噻唑烷甲酸酯的合成、结构和体外抗癌活性

利用三有机锡氢氧化物和手性配体（4R）-3-[[（2S）-5-氧-2-吡咯烷基]羰基]-4-噻唑烷甲酸（HL）反应合成了3个三有机锡（4R）-3-[[（2S）-5-氧-2-吡咯烷基]羰基]-4-噻唑烷甲酸酯R₃SnL[1,R=c-C₆H₁₁（a）,C₆H₅（b）,C₆H₅C（CH₃）₂CH₂（c）],通过元素分析、IR、¹H NMR和X-射线单晶衍射表征了其结构。化合物1a属正交晶系,P2₁2₁2₁空间群;化合物1b属单斜晶系,P2₁空间群。二者均为由羧基氧和内酰胺羰基氧桥联配位形成的右螺旋链状有机锡配位聚合物,锡原子具有五配位[SnC₃O₂]畸变三角双锥构型。化合物1a和1b对体外2种人癌细胞Colo205和Bcap37增殖均有强的抑制作用,其活性为1b >1a。     

Synthesis of lomazarin and norlomazarin, pigments from Lomandra hastilis

5,8-Dihydroxy-2,3,6-trimethoxy-7-ethyl-1,4-naphthoquinone (1) was used to synthesize in high yield 5,8-dihydroxy-7(1′-hydroxyethyl)-2,3,6-trimethoxy-1,4-naphthoquinone (lomazarin, 3), a pigment from Lomandra hastilis. Alkaline hydrolysis of lomazarin produced mainly 5,6,8-trihydroxy-2,3-dimethoxy-1,4-naphthoquinone (9) through a retro-aldol decomposition of the 6-keto-form of 5,6,8-trihydroxy-7(1′-hydroxyethyl)-2,3-dimethoxy-1,4-naphthoquinone (13b) formed during the reaction. 2,5,8-Trihydroxy-7(1′-hydroxyethyl)-3,6-dimethoxy-1,4-naphthoquinone (norlomazarin, 4a), a pigment of L. hastilis, and its 3,5,8-trihydroxy-7(1′-hydroxyethyl)-2,6-dimethoxy isomer 4b were formed as a difficultly separable mixture in addition to quinone 9. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 581–584, November–December, 2008.     

金属离子导向自组装的磺酰化对氨基苯甲酸配合物的合成与表征

用普通溶液法合成了4个配合物：[Cu（Ts-p-aba）₂（phen）（H₂O）]_n（1）、[Zn（Ts-p-aba）₂（phen）（H₂O）]·H₂O（2）、[Pb（Ts-p-aba）₂（phen）]2（3）和{[Pb（Ts-p-aba）（phen）（NO₃）]（DMF）}_n（4）（Ts-p-aba=N-对甲苯磺酰对氨基苯甲酸,phen=菲咯啉,DMF=N,N-二甲基甲酰胺）。X-射线单晶衍射结果表明：配合物1和2均为三斜晶系,P1空间群。配合物1的中心铜离子处于变形的八面体配位环境,并通过配体N-对甲苯磺酰对氨基苯甲酸扩展为一维直线链结构;配合物2是个单核分子,锌离子的配位多面体为四角锥体。配合物3和4均为单斜晶系,P2₁/c空间群。配合物3由配体N-对甲苯磺酰对氨基苯甲酸桥联成二聚体,铅离子处于变形的八面体配位环境;配合物4是具有一维链状结构的配位聚合物,铅离子处于变形的一面心八面体配位环境。另外,对4个配合物的热稳定性、电化学性能和荧光性质也进行了研究。     

Synthese und Reaktionsverhalten von 3-(Bis(alkylthio)methylen)-3H-isobenzofuran-1-on-und 2-(Bis(alkylthio)methylen)-3(2H)-benzofuranon-Derivaten

Summary 3(Bis(alkylthio)methylene)-3H-isobenzofuran-1-ones2a–e and 2-(bis(alkylthio)methylene)-3(2H)-benzofuranone derivatives4a–c are obtained by reaction of phthalides1a–d or 3(2H)-benzofuranone (coumaranone3), respectively, with carbon disulfide under basic conditions followed by alkylation. The reaction behaviour of the new compounds2 and4 is investigated. 2-((2-Dimethylthio-1-oxo)ethyl)benzoic acid N,N-dimethylamide (7a) and 2-((2-dimethylthio-1-oxo)ethyl)-benzoic acid 2-methylpiperidide (7b) are surprisingly formed instead of the methylthio substitution products by treatment of2a with the corresponding amine in the presence of aluminum chloride.

Herrn Professor Dr. Dr. h. c.Waldemar Adam zum 60. Geburtstag gewidmet     

Synthesis, spectral characterization and redox properties of iron (II) complexes of 1-alkyl-2-(arylazo)imidazole

Iron (II) complexes of 1-alkyl-2-(arylazo)imidazoles (p-R-C₆H₄-N=N-C₃H₂NN-1-R′, R = H (a), Me (b), Cl (c) and R′ = Me (1/3), Et (2/4) have been synthesized and formulated astris-chelates Fe(RaaiR′) ₃ ²⁺ . They are characterized by microanalytical, conductance, UV-Vis, IR, magnetic (polycrystalline state) data. The complexes are low spin in character,t _2g ⁶ (Fe(II)) configurations.     

Crystal structure and vibrational spectra of pyridine-2,6-dithio-carbomethylamide

The crystal structure of Pyridine-2,6-dithio-carbomethylamide (PDTA) is described: C₉H₁₁N₃S₂, monoclinic, P2₁/c,Z=4,a=6.000 (1) Å,b=8.840 (1) Å,c=21.452 (1) Å, =105.47 (1)^o,d _x=1.47 gcm^–3. The structure was solved with direct methods and refined to a conventionalR-factor of 0.047. The molecule is nearly planar in the crystal. There are possibly weak intramolecular H-bonds between the two amide nitrogens and the pyridine nitrogen and intermolecular H-bonds between two amide nitrogens and one thioamide sulfur atom. The IR andRaman spectra ofPDTA and deuteratedPDTA are discussed.

---

Kristallstruktur und Schwingungsspektren von Pyridin-2,6-dithiocarbomethylamid

Zusammenfassung Die Kristallstruktur von Pyridin-2,6-dithiocarbomethylamid (PDTA) wurde bestimmt: C₉H₁₁N₃S₂, monoklin, P2₁/c,Z=4,a=6,000 (1) Å,b=8,840 (1) Å,c=21,452 (1) Å, =105,47 (1)^o,d _x=1,47 gcm^–3. Das Phasenproblem wurde mittels direkter Methoden gelöst und die Struktur bis zu einemR-Faktor vonR=0,047 verfeinert. Das Molekül ist im Kristall nahezu planar. Das Vorliegen schwacher intramolekularer Wasserstoffbrücken zwischen den beiden Thioamid-Stickstoffatomen und dem Pyridinstickstoff sowie intermolekularer Wasserstoffbrücken zwischen Thioamid-Stickstoff- und Thioamid-Schwefelatomen wird postuliert. IR- undRaman-Spektren vonPDTA und deuteriertemPDTA werden diskutiert.

     

A Simple and Eco-Compatible One-Pot Synthesis of New Symmetrical Dithiocarbamate Podands and Their Dynamic NMR Studies

Abstract

A simple and eco-compatible synthesis of podands as 4_a-i is performed using amines (3_a-c ), CS₂, and dichlordiamides (DCDs) (2_{a, c} ) in the absence of a catalyst in water. Three reacting DCDs (2_a-c ) were obtained in the reaction of aromatic diamines (1_{a, c} ) with chloroacetyl chloride. Dynamic NMR spectroscopic data of three series of podands (4_a-c , 4_d-f , and 4_g-i ) are discussed and their free energies of activations are calculated (ΔG ^≠ _c s) at coalescence temperatures. The ΔG ^≠ _c of these podands were attributed to conformational isomerization in the range of 14.7–17 kcal/mol due to rotation and resonance effects about the thioamide C?N bond.

[Supplementary materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfer, and Silicon and the Related Elements for the following free supplemental files: Additional figures.]     

Vergleichende Reaktivitätsuntersuchungen am neuen Codimeren aus Malonitril und Cyanessigester an Carbonylverbindungen

The reactivity of 3-amino-2,4-dicyano-methyl-(1d) and-ethyl-crotonate (1e), resp., a new type of codimer from malononitrile and cyanoacetate, was investigated. Condensation reactions with aromatic aldehydes (2a-g), with heterocyclic aldehydes (2j-l), nitrosobenzenes (3a-c) ando-hydroxybenz-and-naphtaldehydes (4a-f), resp., are described, the differences in reactivity, compared with dimer malononitrile and dimeric forms of cyanoacetate (1a-c) are negligible. Condensation compounds of1a with cycloalkanones (5a-c) are able to cyclise with sulfur to cycloalkanonothieno-pyridines (6a-b), while the cycloalkano-derivatives of1d gave no ring closure.

Herrn Prof. Dr.O. E. Polansky zum 60. Geburtstag in Erinnerung an gemeinsame Tätigkeiten auf dem Gebiet der Nitrilchemie gewidmet.     

Komplexe des zweiwertigen Molybdäns,Derivate des Oktahalodimolybdat(II)-Ions, 4. Mitt.: Darstellungen und Kristallstrukturen von zwei neutralen Komplexen mit 4-Methylpyridin

Mo₂Cl₄ Pic ₄·CHCl₃ (A) (Pic=4-methylpyridine) and Mo₂Br₄ Pic ₄ (B) crystallize in the monoclinic space group.A inC2/c (No. 15) witha=15.175 (4),b=10.847 (2),c=19.946 (6) and =104.52 (2)°;D _o=1.71 (2),D _c =1.72 gcm^–3 forZ=4.B inP2_l/n (No. 14) witha=9.270 (3),b=16.614 (5),c=9.305 (3) and =91.96 (5)°;D _o=2.03 (3),D _c =2.05 gcm^–3 forZ=2.Two halogens and 4-methylpyridines of the MoX ₂ Pic ₂ group are in the trans position. Mo–Mo bond lengths are 2.153 96) forA and 2.150 92) forB. Both molecules are situated on the inversion center resulting in the eclipsed configuration of the ligands around the molybdenum pair. The structure ofB has been refined to the conventionalR factors of 0.08 and 0.098. Disorder on the part of 4-methylpyridines and chloroform molecules stopped the refinement ofA at the endR value of 0.175.Mean Mo–X and Mo–N bonding distances are 2.40 (2), 2.25 (5) forA and 2.53 (3), 2.25 (1) forB.

     

金属离子导向自组装的磺酰化对氨基苯甲酸配合物的合成与表征

用普通溶液法合成了4个配合物:[Cu(Ts-p-aba)2(phen)(H2O)]n(1)、[Zn(Ts-p-aba)2(phen)(H2O)]·H2O(2)、[Pb(Ts-p-aba)2(phen)]2(3)和{[Pb(Ts-p-aba)(phen)(NO3)](DMF)}n(4)(Ts-p-aba=N-对甲苯磺酰对氨基苯甲酸,phen=菲咯啉,DMF=N,N-二甲基甲酰胺)。X-射线单晶衍射结果表明:配合物1和2均为三斜晶系,P1空间群。配合物1的中心铜离子处于变形的八面体配位环境,并通过配体N-对甲苯磺酰对氨基苯甲酸扩展为一维直线链结构;配合物2是个单核分子,锌离子的配位多面体为四角锥体。配合物3和4均为单斜晶系,P21/c空间群。配合物3由配体N-对甲苯磺酰对氨基苯甲酸桥联成二聚体,铅离子处于变形的八面体配位环境;配合物4是具有一维链状结构的配位聚合物,铅离子处于变形的一面心八面体配位环境。另外,对4个配合物的热稳定性、电化学性能和荧光性质也进行了研究。     

Synthesis of Novel New 2-(2-(4-((3,4-Dihydro-4-oxo-3-aryl quinazolin-2-yl)methyl)piperazin-1-yl)acetoyloxy)-2-phenyl Acetic Acid Esters

Stereoselective diazotization of (S)-2-amino-2-phenyl acetic acid (L-phenyl glycine) (4) with NaNO₂ in 6% H₂SO₄ in a mixture of acetone and water gave optically pure (S)-2-hydroxy-2-phenyl acetic acid (L-mandelic acid) (5). Esterification, gave (S)-2-hydroxy-2-phenyl acetic acid esters (6). The latter was treated with chloroacetyl chloride in the presence of triethylamine (TEA) in dichloromethane (DCM) to yield (S)-2-chloroacetyloxy phenyl acetic acid ester (2). In another sequence, the reaction of 2-(chloromethyl)-3-arylquinazolin-4(3H)-one (9) treated with N-Boc piperazine, followed by deprotection of the Boc group, to obtain 3-aryl-2-((piperazin-1-yl)methyl) quinazolin-4(3H)-one (3). Reaction of 2 with 3 in the presence of K₂CO₃ and KI gave the title compound, 2-(2-(4-((3,4-dihydro-4-oxo-3-arylquinazolin-2-yl)methyl)piperazin-1-yl) acetoyloxy)-2-phenyl acetic acid esters (1). The structures of all the new compounds obtained in the present work are supported by spectral and analytical data.     

Strukturelle Abwandlungen an partiell silylierten Kohlenhydraten mittels Triphenylphosphan-Azodicarbonsäureester, 5. Mitt.: Transformationen an Glykonolactonen

Reaction ofD-glucono-1,5-lactone1 with two equivalents oft-butyldimethylchlorosilane yields via a ringcontraction 2,6-bis-O-(t-BDMSi)-D-glucono-1,4-lactone2a as main product and a small amount of 5,6-bis-O-(t-BDMSi)-D-glucono-1,4-lactone2c. Under the same conditionsL-mannono-1,4-lactone3 is transformed to the derivatives 2,6-bis-O-(t-BDMSi)-L-mannono-1,4-lactone3a and 3,6-bis-O-(t-BDMSi)-L-mannono-1,4-lactone3c as the minor product. 2,6-bis-O-(t-BDMSi)-D-galactono-1,4-lactone4a and 2,6-bis-O-(t-BDMSi)-D-gulono-1,4-lactone5a are also prepared from the corresponding glyconolactones4 and5. Whereas the compounds2a, 2c, 4a and5a withAc ₂O-pyridine give the bisacetylderivatives2b, 2d, 4b and5b, 3c is converted by an accompanying migration of one silylgroup to the 5,6-bis-O-(t-BDMSi)-2,3-bis-O-acetyl-L-mannono-1,4-lactone3d. The gluconolactone derivative2a reacts easily withTPP/DEAD/HX to the 5-X-L-idono-1,4-lactone derivatives6a (X=N₃),6b (X=p-NO₂-C₆H₄COO) and6c (3-O-acetylderivative of6a). Treating6b with a second equivalentTPP/DEAD/HX leads to the unsaturated sugarlacton7b. Without an external nucleophile2a affords withTPP the mixture of 2,6-bis-O-(t-BDMSi)-3,5-carbonato-D-glucono-1,4-lactone2c, 3,5-anhydro-L-idono-1,4-lactone8 and 3,6-anhydro-D-glucono-1,4-lactone9. Analogous procedures applied to4a yield theL-altronolactonoderivatives10a, 10b and10c, the unsaturated sugarlactone11b on the one and the 3,5-carbonatogalactonolactone4c and the 2,6-bis-O-(t-BDMSi)-3-desoxy-5-ethoxycarbonyl-D-threo-hex-2-en-1,4-lactone12 on the other hand.Whereas the bis-silyletherderivative3a is transformed by the title system exclusively by an elimination process to13, the derivative5a affords withTPP/DEAD without any elimination the 3,6-anhydrosugar14. Partial desilylation of14 followed by acetylation gives the derivatives14a and14b.Structural elucidations were achieved by¹H-NMR-analysis. In some cases also CD-measurements allowed suitable correlations.

Mark, E., Zbiral, E., Brandstetter, H. H., 4. Mitt., Mh. Chem.111, 289 (1980).