Über das bicyclische 2,6‐Methylenpiperidin

Braun, Julius v.; Haensel, W. +; Zobel, Friedrich

doi:10.1002/jlac.19284620118

Cited by 5 publications

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“…6-Azabicyclo[3.1.1]heptane was prepared in low yield by cyclisation of trans-3-bromocyclohexylamine in NaOH/H 2 O [14]. 6-Azabicyclo[3.1.1]heptanes were also prepared by intramolecular nucleophilic substitution of a trans-3-bromocyclohexyl-1 ) An attempt to mimic the axial orientation of the glycosidic bond in a distorted b-d-glucopyranoside by an iminosugar in the 1 C 4 conformation resulted in a weak (K i 200 mm) inhibitor of the Cel7B endocellulase from Humicola insolens (family 7) [7], and 2,6-anhydro-1-deoxynojirimycin mimicking the 2,5 B conformation involved in the enzymatic hydrolysis of a-d-glucopyranosides [8] is a very weak inhibitor of several a-and b-glycosidases [9].amine (83% yield) [15], a trans-3-[(methylsulfonyl)oxy]cyclohexylamine (22%) [16], and a trans-3-azidocyclohexanol (24%) [17].…”

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Electrophilic Bromination of N‐Acylated Cyclohex‐3‐en‐1‐amines: Synthesis of 7‐Azanorbornanes

Kapferer

Vasella

2004

Helvetica Chimica Acta

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The intramolecular bromo-amidation and the dibromination-cyclisation of the N-acylcyclohex-3-en-1-amines 4, 8, 9, 11, 13, 14, and 16 was studied in view of the synthesis of bicyclic amines that are of interest as building blocks and potential glycosidase inhibitors. The trifluoroacetamides 4, 9, and 14 reacted with Nbromosuccinimide (NBS) in AcOH to give dihydro-1,3-oxazines in good yields. The stereoselectivity of the dibromination of the alkenes 8 and 9 depends on the nature of the protecting group, the reagent, and the reaction conditions. Br 2 in CH 2 Cl 2 transformed the alkenes 8 and 9 predominantly into diaxial trans,transdibromides. Bromination of 9 with PhMe 3 NBr 3 or with Br 2 in the presence of Et 4 NBr gave predominantly the diequatorial trans,cis-27 besides some trans,trans-28. A similar bromination of the C(5)-substituted N-acyl-4-aminocyclohexenes 11, 13, 14, and 16 with PhMe 3 NBr 3 was accompanied by intramolecular side reactions that were suppressed by the addition of excess Et 4 NBr. Under these conditions, 11 gave diastereoselectively transdibromides, while its reaction with Br 2 gave trans-dibromides along with the dihydrooxazinone 31. Also the carbamate 13 reacted with PhMe 3 NBr 3 /Et 4 NBr selectively to the trans-dibromide 32 and with Br 2 to the transdibromides 32 and 33, the dihydrooxazinone 34, and the bicyclic ether 35. Similarly, the trifluoroacetamide 14 provided the dibromide 36 (89%), while its reaction with Br 2 led to the dihydrooxazine 22, and the dibromides 36 and 37. The N-benzyl-N-Boc derivative 16 did not yield any dibromide; it reacted with PhMe 3 NBr 3 /Et 4 NBr to the dihydrooxazinone 38, and with Br 2 to the oxazinone 38 and the bicyclic ether 39. The high stereoselectivity of the bromination with PhMe 3 NBr 3 /Et 4 NBr suggests an anchimeric assistance of the NHR substituent. Deprotection, cyclisation, and carbamoylation transformed the dibromides 27, 29, and 32 into the 7-azanorbornanes 42, 49, and 53. The diols 45 and 57 were obtained from 42 and 53 via HBr elimination and stereoselective dihydroxylation; they proved weak inhibitors of several glycosidases. In no case could the formation of a bicyclic azetidine (6-azabicyclo[3.1.1]heptane) from the dibromides 26 and 30 be observed.

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Electrophilic Bromination of N‐Acylated Cyclohex‐3‐en‐1‐amines: Synthesis of 7‐Azanorbornanes

Kapferer

Vasella

2004

Helvetica Chimica Acta

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“…Reaction of 2,6-pyridine dicarboxylic acid dichloride 22 with diamine 23 [13] led to diamide 24 [14] in 34% yield. The following ring closure with 5-t-bu-isophthalic acid dichloride 25 produced macrocycle 9 [15] in 51% yield (Scheme 3).…”

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confidence: 98%

Template synthesis of rotaxanes with carbamate-linked axles

Braun

Hünten

Vögtle³

1999

J. prakt. Chem.

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Non-ionic template effects [1] proved to be a successful concept to synthesize supramolecular architectures [2], especially hydrogen bond-mediated catenane [3] and rotaxane [4] formation [5].In the beginning aromatic diacid dichlorides were believed to be the guests to fit into tetralactame macrocycles. Reaction with bulky amine stoppers in the presence of a macrocycle led to amide-based rotaxanes. Yet by replacing the aromatic diacid dichloride "guests" with aliphatic ones it was even possible to synthesize amidebased rotaxanes with aliphatic building blocks [6] Abstract. Proceeding from diisocyanates 4 and 10 -13, (4-hydroxyphenyl)triphenylmethane 14 and tetralactame macrocycles 1, 2 and 9 the threading synthesis of rotaxanes 16 -21 containing carbamate units in the axle is described. In addition to aromatic diisocyanates aliphatic ones are firstly π-stacking seemed not to be necessary for rotaxane formation. In 1997 we were able to introduce diisocyanates [7] as building blocks. Treatment of macrocycles 1 [8] and 2 [9] with diisocyanates 3 and 4 and further reaction with bulky amine stoppers 5 led to rotaxanes 6 -8 with urea-linked axles [10] in 4 -11% yield (Scheme 1). First attempts to synthesize these rotaxanes at room temperature failed, so we raised the reaction temperature to 40 °C. Although a rise of temperature is weakening the hydrogen bonds [11] between macrocyclic amide host and carbonylic guest, we were able to creintroduced as building blocks in rotaxane chemistry. The template synthesis of the new tetralactame macrocycle 9 with a pyridine unit is presented. It is used as wheel in a rotaxane synthesis towards the carbamate-linked rotaxane 21.Scheme 1 Synthesis of rotaxanes containing urea-linked axles 542

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Untersuchungen an Cyclopropanverbindungen, IV. Über die Bildung von Bicyclo[3.1.0]hexanol‐(2) aus Δ³‐Cyclohexenyl‐Derivaten

Hanack

Keberle

1963

Chem. Ber.

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So ergibt die Addition von Brom an Cyclohexadien-(1.4) ausschliealich 4.5-Dibromcyclohexen-(1)4.5), wahrend die PRbvosT-Reaktion von Cyclohexadien-(1.4) mit Silberbenzoat und Jod quantitativ zu A~-Cyclohexen-diol-(4.5)~~6) fiihrt. Eine weitere Moglichkeit zu Bicyclo[3.1 .O]hexan-Derivaten durch eine Homoallylumlagerung zu gelangen, besteht in der Desaminierung von A3-Cyclohexenylamin (V; X = NHZ) und der Solvolyse von Sulfonsaureestern von AS-Cyclohexenol (V; X = OS02R). Das sich bei beiden Reaktionen bildende Homoallylkation (VI) 1) 111. Mitteil.: M. HANACK und K. GORLER, Chem. Ber. 96, 2121 [1963].

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Über das bicyclische 2,6‐Methylenpiperidin

Abstract: Uer eine von uns und R. S. Cahn konnten unliingst') bei ihren die Konstitutionsfrage des Kodeins betreff'enden Versnchen zeigen, da6 die zwei im Verhaltnis von cis-nnd ') 8.461, 55 (1926).

Cited by 5 publications

References 3 publications

Electrophilic Bromination of N‐Acylated Cyclohex‐3‐en‐1‐amines: Synthesis of 7‐Azanorbornanes

Electrophilic Bromination of N‐Acylated Cyclohex‐3‐en‐1‐amines: Synthesis of 7‐Azanorbornanes

Template synthesis of rotaxanes with carbamate-linked axles

Untersuchungen an Cyclopropanverbindungen, IV. Über die Bildung von Bicyclo[3.1.0]hexanol‐(2) aus Δ³‐Cyclohexenyl‐Derivaten

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Über das bicyclische 2,6‐Methylenpiperidin

Abstract: Uer eine von uns und R. S. Cahn konnten unliingst') bei ihren die Konstitutionsfrage des Kodeins betreff'enden Versnchen zeigen, da6 die zwei im Verhaltnis von cis-nnd ') 8.461, 55 (1926).

Cited by 5 publications

References 3 publications

Electrophilic Bromination of N‐Acylated Cyclohex‐3‐en‐1‐amines: Synthesis of 7‐Azanorbornanes

Electrophilic Bromination of N‐Acylated Cyclohex‐3‐en‐1‐amines: Synthesis of 7‐Azanorbornanes

Template synthesis of rotaxanes with carbamate-linked axles

Untersuchungen an Cyclopropanverbindungen, IV. Über die Bildung von Bicyclo[3.1.0]hexanol‐(2) aus Δ3‐Cyclohexenyl‐Derivaten

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Untersuchungen an Cyclopropanverbindungen, IV. Über die Bildung von Bicyclo[3.1.0]hexanol‐(2) aus Δ³‐Cyclohexenyl‐Derivaten