bluuebunny/crossref_metadata_2025_split huggingface dataset:
Decomposition and disproportionation of hydrazyl radicals and hydrazo compounds derived from azo dyes
Authors: Heijkoop G. , van Beek H. C. A. 
Published: September 2010

AbstractThe mechanisms of decomposition and disproportionation of hydrazyl radicals and hydrazo compounds, derived from azo dyes, have been studied by flash photolysis, flow experiments and fluorescence spectrometry. The hydrazyl radicals undergo a combined decomposition and oxidation process, resulting in the formation of amines and iminoquinones, and regeneration of part of the amount of dye used in their preparation. Hydrazo compounds are formed upon further photo‐reduction of hydrazyl radicals, and decompose in a similar fashion as the latter.
Hydrogenation of Dewar‐benzene derivatives. II. Heterogeneous and homogeneous hydrogenation of dimethyl tetramethylbicyclo [2.2.0]hexa‐2,5‐diene‐2,3‐dicarboxylate and related compounds
Authors: van Rantwijk F. , Timmermans G.J. , van Bekkum H. 
Published: September 2010

AbstractDimethyl tetramethylbicyclo[2.2.0]hexa‐2,5‐diene‐2,3‐dicarboxylate (1) and some related compounds were hydrogenated in the presence of a number of Group VIII metal catalysts. Heterogeneous hydrogenation under ambient conditions resulted in exo,exo addition of one mole of hydrogen. The regioselectivity was strongly dependent on the catalyst, and on the nature and steric requirements of the substituents. Hydrogenation of 1 in the presence of a homogeneous platinum‐tin catalyst resulted in exclusive hydrogenation of the ester‐substituted double bond; exo,endo hydrogenation was involved for 16%.
Selective removal of phenolic hydroxyl groups of morphinan derivatives synthesis of rac. N‐formyl‐3‐methoxy‐6‐oxomorphinan (1)
Authors: Beyerman H.C. , Buurman E. , Lie T.S. , Maat L. 
Published: September 2010

AbstractThe hydroxyl group of N‐formyl‐2‐hydroxy‐3‐methoxy‐6‐oxomorphinan (7) can be readily etherified with 5‐chloro‐1‐phenyltetrazole. The etherification of isomers with the hydroxyl group in position 4 scarcely takes place, if at all. Catalytic hydrogenolysis of the ether of 7 gives dehydroxylation of 7 to N‐formyl‐S‐methoxy‐6‐oxomorphinan (1).
Vilsmeier formylation of vinylcyclopropanes II
Authors: Traas P.C. , Boelens H. , Takken H.J. 
Published: September 2010

AbstractVilsmeier formylation of vinylcyclopropanes 1 (c‐C3H5CR1CHR2, R1 = alkyl, cycloalkyl, phenyl and vinyl, R2 = hydrogen and alkyl), affords the corresponding 3‐cyclopropylacroleïns in excellent yields (75‐95%). Vinylcyclopropanes without an α‐substituent (R1 = H) react very sluggishly and give poor yields (10‐20%) with the exception of the parent compound, vinylcyclopropane (65%), and dehydrocycloisolongifolene (90%). The reaction is not‐stereospecific, supporting the intermediacy of a carbenium ion. Despite the interaction with a neighbouring cyclopropyl group the ring survives the formylation without being ruptured.The reactivity towards the Vilsmeier reagent is very much affected by the size of the substituent on the reactive centre of the vinylcyclopropane system. In some cases double bond migration to the more stable or more accessible position is observed prior to formylation. The course of the former process is strongly influenced by the dimethylformamide concentration.
Regiospecific γ‐alkylation and acylation of 1,3‐cyclohexanedione enol ethers
Authors: de Groot Ae. , Jansen B. J. M. 
Published: September 2010

AbstractEnol ethers of cyclic β‐diketones can be alkylated and acylated in high yields at C(6). When this position is blocked, alkylation takes place at C(2).
Réaction d'oximation de cétones II. Mécanisme de l'étape d'addition, structure et position de l'état de transition
Authors: Lamaty G. , Natat A. , Petitjean A. , Roque J. P. 
Published: September 2010

AbstractLes constantes de vitesse d'addition neutre, ko, et acido‐catalysée, kH, de l'hydroxylamine sur l'acétone, la cyclohexanone, la cyclopentanone, la cycloheptanone et sur neuf acétophénones ont été mesurées dans l'eau à 25°. Les valeurs des constantes ρ de Hammett sont respectivement égales à +0,78 et +0,45 pour la réaction neutre et la réaction acido‐catalysée. Le mécanisme des deux additions et la structure de leurs états de transition sont discutés. Dans les deux cas le processus de transfert de proton parait être “concerté” et l'état de transition proche de l'état initial.
Ring transformations in reactions of heterocyclic compounds with nucleophiles (XII): A 15N and 14C study of the conversion of pyrimidine into 5‐ethyl‐2‐methylpyridine
Authors: Oostveen E. A. , van der Plas H. C. 
Published: September 2010

AbstractThe mechanism of the conversion of pyrimidine into 5‐ethyl‐2‐methylpyridine has been investigated. It has been proved, using the labelled compounds [1,3‐15N]pyrimidine, [4,6‐14C]pyrimidine and [5‐14C]pyrimidine, that this reaction proceeds via a mechanism, in which the pyrimidine ring is fragmentated into two molecules of HCN and one molecule of N‐methylacetaldimine. Four molecules of this imine undergo an aldol type condensation leading to 5‐ethyl‐2‐methylpyridine.
Bis(trichloromethanesulfenyl)amine from the reaction of nitrogen trichloride with dimethyl disulfide: Synthesis and reactions
Authors: Trompen W. P. , Geevers J. 
Published: September 2010

AbstractReaction of nitrogen trichloride with dimethyl disulfide in chloroform solution affords bis(trichloromethanesulfenyl)amine (2). Compound 2 is converted by trichloromethanesulfenyl chloride into tris(trichloromethanesulfenyl)amine (3) and by trifluoromethanesulfenyl chloride into bis‐(trichloromethanesulfenyl)trifluoromethanesulfenyl amine (4). Acylation of 2 with acetyl chloride and with benzoyl chloride respectively, is described The reaction of 2 with thionyl chloride affords sulfinyl‐(trichloromethanesulfenyl)amine (7).
Isomérisation d'azides intermédiaries dans la synthèse de phényl‐1 cyclohexylamines substituées au cyclohexane
Authors: Geneste P. , Kameuka J. M. , Herrmam P. , Moreau J. 
Published: September 2010

AbstractAn important step in a new synthesis of phenylcyclohexylamines, the conversion of 1‐phenylcyclohexanols into the corresponding azides, is studied in some detail. The slow epimerization of the azides allows isolation of both the kinetic and the thermodynamic products.From the chemical behaviour of the different species in the reaction medium (alcohols, azides, ole fines) it is concluded that the common intermediate probably is a carbocation.
Deazapurine derivatives XV: Syntheses of some mono‐ and difluoroimidazo[4,5‐b]‐ and ‐[4,5‐c]pyridines
Authors: Kroon C. , van den Brink A. Maassen , Vlietstra E.J. , Salemink C.A. 
Published: September 2010

AbstractThe syntheses of 5‐fluoro‐, 5,7‐difluoroimidazo[4,5‐b]pyridine (5b and 5e”) and 4‐fluoro‐, 6‐fluoro‐ and 4,6‐difluoroimidazo[4,5‐c]pyridine (5a, 5c and 5e) are described. The syntheses are achieved through fluorodechlorination of di‐ and trichloro‐3‐nitropyridines, followed by monoamination, reduction and ring‐closure with diethoxymethyl acetate. The reactivity of the new fluoro‐imidazopyridines is investigated briefly.
The chemistry of small ring compounds. Part 32: Synthesis of some 1‐arylcyclopropanols and 1‐arylcyclopropyl chlorides
Authors: van der Vecht J.R. , Steinberg H. , de Boer Th.J. 
Published: September 2010

AbstractThe synthesis of some cyclopropanes with a trimethylsilyloxy group and an aryl group carrying electron‐donating substituents at the same ring carbon atom is described. These compounds can be used as precursors for 1‐aryl‐cyclopropanols and ‐cyclopropyl chlorides.
Reactive additives for polyethylene terephthalate I: Preparation of ketenimines
Authors: Sikkema D.J. , Molenaar E. , van Guldener D.B. 
Published: September 2010

AbstractA number of synthetic routes to fully aromatic bisketenimines, versatile additives for processing polyethylene terephthalate into high‐performance tyre yarns, have been studied. A convenient procedure is presented here: conversion of a bis‐gem‐dichloroaziridine with sodium iodide or zinc.
Preparation, properties and crystal structure of hexakis(N,N‐di‐n‐butyldithiocarbamato)(copper(III), ‐copper(II), ‐gold(III)) tetrabromodi‐μ‐bromodimercurate(II), [(Cu2Au)(Bu2dtc)6][Hg2Br6]
Authors: Gal A.W. , Beurskens Gezina , Cras J.A. , Beurskens P.T. , Willemse J. 
Published: September 2010

AbstractThe preparation, some spectral properties and the crystal structure of a compound of composition [Cu2Au(Bu2dtc)6][Hg2Br6]*, are reported. The crystal structure is isomorphous with the tricopper analogue: [Cu3(Bu2dtc)6][Cd2Br6].X‐Ray data for the present compound are: space group Pī; unit cell: a = 12.614(4), b = 13.691(4), c = 12.502(4) Å, α = 96.37(4)°, β = 91.47(4)°, γ = 85.43(4)°, with one formula unit per cell. Atomic parameters were refined to a conventional R‐value of 0.056 for 1752 independent non‐zero reflections. The structure consists of two ionic units: [Cu2Au(Bu2dtc)6]2+ and [Hg2Br6]2–. The non‐centric cation is situated at a centrosymmetric position, with disordered Cu(III) and Au(III) attached to a central Cu(II) atom.This central Cu(II) atom has an apically distorted octahedral S‐coordination, with Cu–S distances of 2.33(1), 2.28(1), and 3.20(1) Å. The disordered [Cu(III), Au(III)] positions have five‐fold pyramidal S‐coordination with distances of 2.25(1), 2.26(1), 2.29(1), 2.26(1) and 3.15(1) Å.
Photodehydrocyclisations of stilbene‐like compounds XVI: Photoreactions of α‐(9‐phenanthryl)stilbene and 1‐(9‐phenanthryl)‐1‐phenylethylene
Authors: Laarhoven W.H. , Cuppen Th. J. H. M. 
Published: September 2010

AbstractThe regular photocyclisation of α‐(9‐phenanthryl)stilbene (1) to 9‐phenylbenzo[g]chrysene (2) is accompanied by formation of 4,5‐diphenylacephenanthrylene (3). A similar photocyclisation, providing a five‐membered ring, occurs on irradiation of 1‐(9‐phenanthryl)‐1‐phenylethylene (4) which yields a small amount of 5‐phenylacephenanthrylene (5). The structures of3and5were confirmed by comparison of their spectral data with those of acephenanthrylene (10). This was synthesized by photolysis of 1‐(o‐iodobenzylidene)indane (8), followed by dehydrogenation, however,10cannot be obtained by irradiation of 1‐(o‐iodobenzylidene)indene (11). The different photoreactivity of8and11is discussed briefly.
Esters β‐thiocétoniques cyclaniques N° 1 Préparation et séparation des isomères
Authors: Paquer D. , Smadja S. 
Published: September 2010

AbstractTreatment of alicyclic β‐keto esters with a mixture of hydrogen sulfide and hydrogen chloride gives β‐thioxo esters.In some cases three forms of these products have been characterized a thioketone form, a conjugated enethiol form and a non‐conjugated enethiol form.
Ring transformations in reactions of heterocyclic compounds with nucleophiles (XIII) Degenerate ring transformations of N‐methylpyrimidinium salts into 2‐substituted pyrimidines
Authors: Oostveen E.A. , van der Plas H.C. , Jongejan H. 
Published: September 2010

AbstractOn treatment of the quaternary pyrimidinium salts i.e. 1‐methyl‐4‐phenylpyrimidinium iodide and 1‐methyl‐5‐phenylpyrimidinium iodide with cyanamide, O‐methylisouronium chloride or bis[S‐methylisothiouronium] sulfate in basic media, 2‐amino‐4‐phenylpyrimidine and 2‐amino‐5‐phenylpyrimidine are formed respectively. A ring transformation is involved in which the two‐atom fragment N(1)‐C(2) of the pyrimidine ring is replaced by an N‐C fragment of the reagent. On reacting 1‐methylpyrimidinium iodide with benzamidinium chloride or pivalamidinium chloride in a solution of sodium ethoxide in ethanol, 2‐phenylpyrimidine and 2‐tert‐butylpyrimidine are formed respectively.It is proved by 15N‐labelling that this nucleophilic substitution occurs via a ring transformation in which the N(1)‐C(2)‐N(3) fragment of the pyrimidine is replaced by the N‐C‐N fragment of the amidine. These reactions are new examples of a nucleophilic substitution occurring according to an SN(ANRORC) mechanism.
Synthesis of 1,5‐ and l,7‐naphthyridin‐4(1H)‐ones
Authors: Walraven H.G.M. , Choudry G.G. , Pandit U.K. 
Published: September 2010

AbstractThe reaction of 3‐aminopyridine with β‐keto esters followed by thermal cyclization of the corresponding 3‐aminoacrylic esters constitutes a convenient general approach to the synthesis of 1,5‐ and 1,7‐naphthyridine derivatives.
On the reaction of 3‐bromo(chloro)‐1,7‐naphthyridine with potassium amide in liquid ammonia
Authors: van der Plas H.C. , Woźniak M. , van Veldhuizen A. 
Published: September 2010

Abstract3‐Amino‐ and 4‐amino‐1,7‐naphthyridine are obtained from both 3‐bromo‐ and 3‐chloro‐1,7‐naphthyridine on amination with potassium amide in liquid ammonia at −33°. The ratio in which the two amino compounds are formed is completely independent of the nature of the halogen atom, presenting good evidence for the intermediacy of 3,4‐didehydro‐1,7‐naphthyridine. 1HNMR spectroscopy has shown that 3‐chloro‐1,7‐naphthyridine forms with the amide ion a σ‐adduct at C‐2; in a very fast reaction; this adduct formation precedes the formation of the didehydro compound.
Ring expansion of geminal dibromocyclopropanes with silver fluoride. A convenient route to fluorinated medium‐sized rings
Authors: Loozen H.J.J. , Robben W.M.M. , Buck H.M. 
Published: September 2010

AbstractRing opening of the geminal dibromocyclopropanes 1−3 can be effected by treatment with silver fluoride in acetonitrile.In a stereospecific reaction this affords the allylic fluorides 4−8 in moderate yields. This reaction follows the general principles which have been established for silver ion‐catalyzed ring expansions in medium sized rings.Treatment of 7‐exo‐bromo‐7‐endo‐iodobicyclo[4.1.0]heptane (10) with AgF affords 2‐bromo‐3‐fluoro‐1‐cycloheptene (11). On using AgPF6 as a catalyst in the ring opening of 10, a Ritter reaction is observed giving N‐(2‐bromo‐1‐cycloheptene‐3‐yl)acetamide (12).
Eight‐coordinated 1,1‐dithio ligand complexes of molybdenum and tungsten
Authors: Nieuwpoort A. , Steggerda J.J. 
Published: September 2010

AbstractThe physical properties of the dithiocarbamato compounds Mo(R2dtc)4 (R2dtc = R2NCS2−; R = Me, Et, i‐Pr, Bz, Ph; R2 = Tm, Pm, MeBz; Tm = (CH2)4, Pm = (CH2)5) and [M(R2dtc)4]X (M = Mo, W; X = various anions), and the dithio acid compounds M(Rdta)4 (M = Mo, W; Rdta = RCS2−; R = Tol, Naf; Tol = p‐toluoyl, Naf = 2‐naphthoyl), prepared by oxidative decarbonylation of metal carbonyl complexes with disulfides, have been investigated. Conductivity data and infrared spectra indicate that all compounds contain metal ions coordinated by eight sulfur atoms belonging to four ligands.Voltammetric measurements show for the [Mo(R2dtc)4]°,+ complexes three one‐electron oxidation/reductions, indicating the formation in solution of unstable [Mo(R2dtc)4]− and [Mo(R2dtc)4]2+. The [W(R2dtc)4]+ complexes show only one oxidation and one reduction process in the voltage range studied. The substituent effects on the half‐wave potentials can be described by the Taft relation. The dithio acid complexes show two redox processes, indicating the formation of M(II) and M(V) compounds. The differences between these complexes and the dithiocarbamato complexes are in agreement with the stronger electron donating properties of the dtc ligand.
Photochemical hydroxylation of quinoxalines
Authors: Verbeek J. , Berends W. , van Beek H.C.A. 
Published: September 2010

AbstractIrradiation of quinoxaline (1) in acidic aqueous solution under anaerobic conditions leads to the formation of 5‐hydroxyquinoxaline (4) and the 1,4‐dihydroquinoxaline radical cation (5). The radical cation (5) was characterized by ESR spectroscopy.Under aerobic conditions 5‐hydroxyquinoxaline (4) is the only irradiation product formed. The effect of substituents attached to the benzene nucleus of quinoxaline is analyzed.
Two‐step synthesis of a sex attractant of the male Boll Weevil from isophorone
Authors: Traas P.C. , Boelens H. , Takken H.J. 
Published: September 2010

AbstractVilsmeier formylation of isophorone affords (3‐chloro‐5,5‐dimethyl‐2‐cyclohexenylidene)acetaldehyde (2) in 80 % yield.Catalytic hydrogenation of this unsaturated aldehyde over palladium on charcoal poisoned with sulfur and quinoline gives in quantitative yield (3,3‐dimethylcyclohexylidene)acetaldehyde†, an important component of the sex pheromone complex of the male Boll Weevil (Anthonomus Grandis).
Conversion of (‐)‐N‐formylnordihydrothebainone into (‐)‐dihydrotbebainone and vice versa: (Chemistry of opium alkaloids, Part VII)
Authors: Beyerman H.C. , van Bommel L. , Maat L. , Olieman C. 
Published: September 2010

Abstract(‐)‐N‐Formylnordihydrothebainone (1) was converted into (‐)‐dihydrothebainone (3) by two routes: removal of the formyl group followed by reductive methylation, and direct hydride reduction after protection of the 6‐oxo group in the form of an acetal.The starting material 1 was obtained by demethylation of (‐)‐dihydrothebainone (3), prepared from natural material, to (‐)‐nordihydrothebainone (2), which was formylated with ethyl formate.
C‐Nitroso compounds. Part XXVIII: Generation and reactivity of N‐(1‐chloroalkyl)nitrones obtained by reaction of diazoalkanes with gem‐chloronitroso compounds
Authors: Kayen A. H. M. , de Boer Th. J. 
Published: September 2010

AbstractHitherto unknown N‐(1‐chloroalkyl)nitrones 1, the formal condensation products of ketones and gem‐chloro(hydroxylamino)alkanes have been generated in situ by reaction of diazoalkanes with gem‐chloronitrosoalkanes 3. The existence of transient nitrone species follows from their reaction with tert‐butoxy radicals and with tri‐n‐butylstannane to give nitroxides, the structure of which is supported by ESR.In situ generated N‐(1‐chloroalkyl)nitrones 1 undergo methanolysis in the presence of bases with formation of two oximes and two ketones. This strongly implies a mechanism of solvolysis as outlined in schemes 1 and 2, supported by quantitative product analysis (Table I).
Charge transfer complexes of tetracyanoquinodimethane with 6‐ and 7‐aminoquinolines
Authors: Poradowska H. , Czuba W. , Lorenz K. , Chyla A. 
Published: September 2010

AbstractCharge transfer complexes of tetracyanoquinodimethane with 6‐ and 7‐aminoquinolines have been obtained and their electrical and spectral properties investigated. These complexes possess high conductivities.
Synthesis of acetals using molecular sieves III The use of solid acids as catalysts
Authors: Wortel Th. M. , Esser W. H. , van Minnen Pathuis G. , Taal R. , Roelofsen D. P. , van Bekkum H. 
Published: September 2010

AbstractThe synthesis of acetals from the corresponding carbonyl compounds and alcohols in high yield is described. Commercial silica‐alumina cracking catalysts, Y‐type molecular sieves partially exchanged with multivalent cations and sulfonated polystyrene resins are used as catalysts while a molecular sieve type A serves to shift the equilibrium by adsorbing the water formed. Proper activation of silica‐alumina and Y‐sieve catalyst is essential for obtaining a high catalytic activity. Procedures have been developed to regenerate the catalyst‐adsorbent combination.Compared to earlier techniques the synthesis of acetals has been improved substantially.
Stereochemistry of the reduction of some 2,2,4,5‐tetrasubstituted 1,3‐cyclopentanediones
Authors: Plantema O. G. , de Koning H. , Huisman H. O. 
Published: September 2010

AbstractThe reduction of the oxo functions in ethyl 5‐(6‐ethoxycarbonylhexyl)‐3,3‐dimethyl‐2,4‐dioxocyclopentanecarboxylate (1) with NaBH4, with LiAlH(O‐t‐Bu)3 and by catalytic hydrogenation is described. Four isomeric hydroxycyclopentanones and four isomeric cyclopentanediols were isolated and their stereochemistry was determined, providing 1H‐NMR and 13C‐NMR data which should be useful in structural assignment of isomeric prostaglandin analogues.
Ring transformations in reactions of heterocyclic compounds with nucleophiles Reactions of 4(6)‐alkoxy‐1‐ethyl‐ and 4,6‐dialkoxy‐1‐ethyl‐pyrimidinium tetrafluoroborates with liquid ammonia
Authors: Oostveen E.A. , van der Plas H.C. 
Published: September 2010

AbstractOn treatment with liquid ammonia at −33° the quaternary pyrimidinium salts i.e. 4‐ethoxy‐1‐ethyl‐ (1) and 4,6‐diethoxy‐1‐ethyl‐pyrimidinium tetrafluoroborate (3) undergo amino‐de‐ethoxylation, yielding 1,4‐dihydro‐1‐ethyl‐4‐imino‐pyrimidine hydrogen tetrafluoroborate (7) and a mixture of 1,4‐dihydro‐6‐ethoxy‐1‐ethyl‐4‐imino‐ (9) and 1,6‐dihydro‐4‐ethoxy‐1‐ethyl‐6‐imino‐pyrimidine hydrogen tetrafluoroborate (11), respectively. 1HNMR and 13CNMR spectroscopic evidence is presented for the fact that compounds 1 and 3 easily give σ‐adducts at position 2. Using 15N‐labelled ammonia it was shown that in these amino‐de‐ethoxylation reactions the substitution at C(4) or C(6) does not involve ring opening but probably occurs via an SN(AEn) process. Reaction of 4‐ethoxy‐1‐ethyl‐2‐phenyl‐ (2), 6‐ethoxy‐1‐ethyl‐4‐phenyl‐ (4), 4,6‐dimethoxy‐1‐ethyl‐2‐phenyl‐ (5) and 4,6‐dimethoxy‐1‐ethyl‐2‐methyl‐pyrimidinium tetrafluoroborate (6) with liquid ammonia gives besides the amino‐de‐ethoxylation product degenerate ring transformations leading to the N‐de‐ethylated products 14–16 and 4(6)‐(ethylamino)pyrimidines 17‐19. The salt 11 and 1,6‐dihydro‐1‐ethyl‐6‐imino‐4‐phenylpyrimidine hydrogen tetrafluoroborate (12) undergo, with potassium hydroxide, a Dimroth rearrangement to pyrimidines 20 and 17, respectively.
Recognition of atropisomerism and thermally labile prochirality, and measurement of barriers to rotation in sulfines (thione oxides) by the use of chiral shift reagents
Authors: Tangerman A. , Zwanenburg B. 
Published: September 2010

AbstractThe sulfines 1–9 in which the o‐positions of the aryl ring A are substituted by methyl groups, have a high rotational barrier about the aryl A to sulfine bond (bond α). Due to this α‐barrier, sulfines 1 and 2 exist as a pair of rotational enantiomers (atropisomerism). The symmetrically substituted sulfines 3,4,7,8 and 9 possess a prochiral centre, viz. the mesityl‐CSO part, provided rotation about bond α is restricted. With rapid rotation about bond α this prochirality disappears (thermally labile prochirality). Chiral lanthanide shift reagents are employed to uncover these chiral properties. The atropisomerism in the sulfines 1 and 2 and the thermally labile prochirality in the sulfines 3,4, 7, 8 and 9 are demonstrated by use of chiral shift reagent. Moreover, chiral shift reagents are successfully used to determine the α‐barrier in the sulfines 3, 4 and 9.
On the formation of allenes in the steroid series III.: Synthesis and reactions of 3‐methoxy‐17α‐hydroxy‐17β‐ethynyl‐1,3,5(10)‐estratriene (“epimestranol”)
Authors: van Dijck L.A. , Lankwerden B.J. , Vermeer J.G.C.M. 
Published: September 2010

Abstract“Epimestranol” (6) has been prepared from the 16α,17‐epoxide 5 by reduction with LiAlH4. The structures of several by‐products have been elucidated and a mechanism for their formation is discussed. Both “mestranol” (3) and “epimestranol” failed to form p‐tosylates and only “mestranol” could be converted into the p‐toluenesulfinate which readily rearranged to the allenic sulfone 14. “Epimestranol” was transformed into a mixture of the two epimeric 17‐sulfones instead of the 17α‐sulfinate.
Synthesis of L‐Nπ‐methylhistidine derivatives (Imidazole chemistry, Part III)
Authors: Beyerman H. C. , Maat L. , Noordam A. , van Zon A. 
Published: September 2010

AbstractL‐Histidine was converted into the methyl ester of (‐)‐(S)‐2‐chloro‐3‐(5‐imidazolyl)‐propionic acid (1). After benzoylation and reaction with trimethyloxonium fluoroborate, this yielded selectively the Nπ‐methyl compound, which was subsequently reduced to the corresponding chloro alcohol (4). The absolute configurations are confirmed by the optical rotatory dispersion and circular dichroism spectra.