Synthesis of 3-Amino-2,2-dimethyl-8-thia-1-azaspiro[4.5]decane

The synthesis of 3-amino-2,2-dimethyl-8-thia-1-azaspiro[4.5]decane is described. Key steps include the addition of prenyl magnesium bromide to a 4-methoxybenzylimine without reversal of stereochemistry and the iodine-initiated aminocyclization to form the azaspirocycle.     

Synthesis and Crystal Structure of 4-(Dichloroacetyl)-1-oxa-4-azaspiro[4.5]decane

<正>The title compound 4-(dichloroacetyl)-1-oxa-4-azaspiro[4. 5] decane (CAS number 71526-07-3, C10H15Cl2NO2, Mr= 252.13) was obtained by the reaction of dichloroacetic acid with 1-oxa-4-azaspiro[4. 5] decane. The crystal is of monoclinic, space group P21ln with the unit cell constants: a = 5.9619(4),b= 10.0066(8), c = 20.0986(4) A,β = 90.194(3)°, V= 1199(4) A3,Z = 4, Dc= 1.397 g/cm3, F(000) = 528, μ(MoKα) = 0.522 mm-1, R = 0.0611 and wR = 0.1656 for 1276 observed reflections (I > 2σ(I)). X-ray analysis reveals that the cyclohexyl adopts a chair conformation and the compound is a chiral one.     

A mass spectrometric study of 1,4-dioxa-8-azaspiro[4.5]decane

The mass spectrum of 1,4-dioxa-8-azaspiro[4.5]decane (4-ethylenedioxypiperidine) showed a prominent peak at m/e 87. Ethylenedioxy ketals commonly give a fragment of m/e 86 and other fragments of higher mass than 87. A mechanism for formation of a m/e 87 fragment was formulated and evidence for this mechanism and the structure of the fragment was obtained by deuterium labelling. Structures and mechanisms of formation of other major fragments were also studied.     

Synthesis of 1-substituted 2-azaspiro[4.5]deca-6,9-dien-8-ones and 2-azaspiro[4.5]deca-1,6,9-trien-8-ones by condensation of 2,6-dimethylphenol with isobutyraldehyde and nitriles

1-Substituted 3,3,7,9-tetramethyl-2-azaspiro[4.5]deca-6,9-dien-8-ones and 3,3,7,9-tetramethyl-2-azaspiro[4.5]deca-1,6,9-trien-8-ones were synthesized by three-component condensation of 2,6-dimethylphenol with isobutyraldehyde and nitriles in concentrated sulfuric acid.     

Synthesis of a New Spiro System: 1-Oxa-7-thia-4-azaspiro[4.5]decane 7,7-Dioxide

Dihydro-2H-1λ⁶-thiopyran-1,1,3(4H)-trione reacted with N-substituted 2-aminoethanols to give derivatives of a new spiro system, 1-oxa-7λ⁶-thia-4-azaspiro[4.5]decane-7,7-diones. No spirocyclic product was obtained by the reaction with unsubstituted 2-aminoethanol, but the corresponding enamine was formed as in the reactions with other primary amines.     

Synthesis and Rearrangement of 1-Substituted 3,3,7-Trimethyl-2-azaspiro[4.5]deca-1,6,9-trien-8-ones

Russian Journal of Organic Chemistry -     

7-(羟甲基)-8-氮杂螺[4.5]癸烷-8-羧酸叔丁酯的合成

以8-氮杂螺[4.5]癸烷-7,9-二酮为原料,通过酰胺还原、N-Boc保护、甲酰化、醛基四步反应还原反应合成得到目标化合物7-(羟甲基)-8-氮杂螺[4.5]癸烷-8-羧酸叔丁酯,总收率29.8％.反应中间体及产物结构经1 H NMR和ESI-MS确证,同时对每步反应条件进行讨论.该研究提供了一种新结构的含氮螺环化合...     

Synthesis of enantiopure 1-azaspiro[4.5]dec-6-en-8-ones from l-proline derivatives

An enantioselective synthesis of protected 1-azaspiro[4.5]dec-6-en-8-one derivatives was achieved using an alkylidene carbene 1,5-CH insertion reaction as the key step.     

Ring-rearrangement metathesis of 1-substituted 7-azanorbornenes as an entry to 1-azaspiro[4.5]decane systems

Several metathesis sequences have been carried out using 7-azanorbornenes as starting materials. The occurrence of several exocyclic olefin patterns in the bridgehead position of this system opens the way to gain interesting spirocyclic compounds, which were achieved using several ring-rearrangement metatheses (RRM). The metathesis products, thus obtained, may be useful for the synthesis of new peptidomimetics and related compounds.     

Synthesis and conformation of 6,8,10-trinitro-1,4-dioxaspiro[4.5]decane

cis, trans-6,8,10-Trinitro-1,4-dioxaspiro[4.5]decane was synthesized by reduction of the corresponding spirocyclic anionic δ-complex with potassium tetrahydroborate. The molecular structure and the conformation of the title compound were established by X-ray diffraction analysis and¹H NMR spectroscopy. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1713–1717, September, 1999.     

Synthesis of 1-substituted 2-azaspiro[4.5]deca-6,9-diene-8-ones and 2-azaspiro[4.5]deca-1,6,9-triene-8-ones by a three-component condensation of 1,2,3-, 1,2,4- or 1,3,5-trimethoxybenzene with isobutyric aldehyde and nitriles

A three-component condensation of 1,2,3- or 1,2,4-trimethoxybenzene with isobutyric aldehyde and alkyl cyanoacetates in the presence of sulfuric acid resulted in the formation of substituted 2-azaspiro[4.5]deca-6,9-diene-8-ones. The same reaction of aromatic nitriles yielded 2-azaspiro[4.5]deca-1,6,9-triene-8-ones; in the case of 1,2,3-trimethoxybenzene corresponding Ritter amides were also observed. The condensation of 1,3,5-trimethoxybenzene with isobutyric aldehyde and alkyl cyanoacetates provided the compounds of the formal Knöevenagel condensation.     

Stereocontrolled syntheses of epimeric 3-aryl-6-phenyl-1-oxa-7-azaspiro(4.5)decane NK-1 receptor antagonist precursors

[structure: see text]. Complementary stereoselective syntheses of individual C3 epimers of the NK-1 receptor antagonist precursor 1 have been developed. Both diastereomers were derived from the common intermediate 3; introduction of the 3S stereocenter in 1a was achieved through hydrogenation of an arylated dihydrofuran, whereas the corresponding stereogenic center in 1b was installed using a stereo- and regioselective alkene hydroarylation.     

Synthesis of enantiopure 3-amino-1-azaspiro[4.5]decan-8-ones by halonium promoted cyclization of amino-tethered cyclohexenes

Haloaminocyclization reactions of polysubstituted γ-aminocyclohexenes give 3-amino-1-azaspiro[4.5]decan-8-one derivatives. The stereocontrol, chemoselectivity (N-attack vs O-attack), and influence of the halonium ion are discussed.     

Retropinacol rearrangement in the synthesis of 3,3,4-trimethyl-2-azaspiro[4.5]deca-1,6,9-trien-8-one derivatives

Russian Journal of Organic Chemistry -     

Spirocyclohexadienones. 4. Synthesis and dienone-phenolic rearrangement of 1-R-3,3-dialkyl-2-azaspiro[4.5]deca-1,6,9-trien-8-ones

The reactions of 1-(p-methoxyphenyl)-2-methylpropan-1-ol or -cyclohexyl-p-methoxybenzyl alcohol with nitriles RCN in concentrated sulfuric acid afforded 1-R-3,3-dialkyl-2-azaspiro[4.5]deca-1,6,9-trien-8-ones. The stability of the latter toward the dienone-phenolic rearrangement depends on the nature of the substituent R. The reaction mechanism was studied by the semiempirical quantum-chemical AM1 method.