Synthesis of cationic dibenzosemibullvalene-based phase-transfer catalysts by di-π-methane rearrangements of pyrrolinium-annelated dibenzobarrelene derivatives

• Heiko Ihmels and
• Jia Luo

Beilstein J. Org. Chem. 2011, 7, 119–126, doi:10.3762/bjoc.7.17

• . Specifically, the close proximity between the methyl group and the methine proton (8b’-H) of the cyclopropane ring gave rise to an NOE in 3eI and 3fI (Scheme 3). The structure of the minor products 3eII and 3fII, although not isolated, were determined by 1H NMR spectroscopic analyses of the photolysates. In

Highly substituted benzannulated cyclooctanol derivatives by samarium diiodide-induced cyclizations

• Jakub Saadi,
• Irene Brüdgam and
• Hans-Ulrich Reissig

Beilstein J. Org. Chem. 2010, 6, 1229–1245, doi:10.3762/bjoc.6.141

• in analogy to our previously described modular approach [33]. As a typical example, the synthesis of precursor 4 is depicted in Scheme 2. Cyclopropane 1 [36][37] was deprotonated with LDA and subsequently alkylated with 2-iodobenzyl iodide, furnishing 2 in moderate yield. Intermediate 2 was then

Systematic investigations on the reduction of 4-aryl-4-oxoesters to 1-aryl-1,4-butanediols with methanolic sodium borohydride

• Subrata Kumar Chaudhuri,
• Manabendra Saha,
• Amit Saha and
• Sanjay Bhar

Beilstein J. Org. Chem. 2010, 6, 748–755, doi:10.3762/bjoc.6.94

• -oxoester to 1,4-diols was finally established (Scheme 11) when substrate 14 [40] (incapable of lactonization due to distal spatial disposition of the oxo- and methoxycarbonyl moieties imposed by the rigidity of the cyclopropane ring system) underwent selective reduction of the oxo-functionality only under

Synthesis of a novel analogue of DPP-4 inhibitor Alogliptin: Introduction of a spirocyclic moiety on the piperidine ring

• Arumugam Kodimuthali,
• Padala Lakshmi Prasunamba and
• Manojit Pal

Beilstein J. Org. Chem. 2010, 6, No. 71, doi:10.3762/bjoc.6.71

• functionalized cyclopropyl ring (step i, Scheme 1) via a conventional C–C bond forming reaction. The reaction proceeded well to afford the functionalized cyclopropane derivative 1 as a result of the formation of two C–C bonds in a single step. Selective reduction of the cyano group of the resulting cyanoester 1

An expedient and new synthesis of pyrrolo[1,2-b]pyridazine derivatives

• Rajeshwar Reddy Sagyam,
• Ravinder Buchikonda,
• Jaya Prakash Pitta,
• Himabindu Vurimidi,
• Pratap Reddy Padi and
• Mahesh Reddy Ghanta

Beilstein J. Org. Chem. 2009, 5, No. 66, doi:10.3762/bjoc.5.66

• cycloaddition of dimethyl acetylenedicarboxylate to the Reissert compound of pyridazine [20], the 1,3-dipolar cycloaddition of pyridazinium dichloromethylide generated by the carbene method [21], and the cycloaddition of alkylidene cyclopropane derivatives to pyridazine in the presence of Pd(PPh3)4 [22

Mitomycins syntheses: a recent update

• Jean-Christophe Andrez

Beilstein J. Org. Chem. 2009, 5, No. 33, doi:10.3762/bjoc.5.33

• methodology was known before 1900 [71], it did not draw much attention in total synthesis because of its lack of efficiency. In the middle of 1970’s Danishefsky and co-workers focused on the systematic study of this reaction and made relevant improvements for both the preparation of the cyclopropane and the

• (Scheme 18). This methodology provided a new entry for the construction of pyrrolidine-indole structures based on the intramolecular opening of an activated cyclopropane [75][76][77]. This work culminated in the synthesis of an advanced intermediate en route to the mitosane series [78]. Compound 67 was

• thermolyzed in refluxing chlorobenzene in the presence of cupric acetonylacetonate to give the cyclopropane adduct in 35% yield (Scheme 19) [79]. The product arose as a 5:1 mixture of diastereoisomers, with the major component 69 having the bulky hexasubstituted phenyl group on the convex face of the bicyclic

New diarylmethanofullerene derivatives and their properties for organic thin- film solar cells

• Daisuke Sukeguchi,
• Surya Prakash Singh,
• Mamidi Ramesh Reddy,
• Hideyuki Yoshiyama,
• Rakesh A. Afre,
• Yasuhiko Hayashi,
• Hiroki Inukai,
• Tetsuo Soga,
• Shuichi Nakamura,
• Norio Shibata and
• Takeshi Toru

Beilstein J. Org. Chem. 2009, 5, No. 7, doi:10.3762/bjoc.5.7

• , Nagoya 466 8555, Japan 10.3762/bjoc.5.7 Abstract A number of diarylmethanofullerene derivatives were synthesized. The cyclopropane ring of the derivatives has two aryl groups substituted with electron-withdrawing and -donating groups, the latter with long alkyl chains to improve solubility in organic

• (Figure 1). The new diarylmethanofullerenes have two aromatic rings on the cyclopropane, having electron-withdrawing and electron-donating groups. The electron-withdrawing groups were expected to increase the electron-accepting ability of fullerene, while the electron-donating groups would decrease the

• the electron-withdrawing nature of the (methoxycarbonyl)phenyl, cyanophenyl, nitrophenyl, (methylsulfonyl)phenyl, and (trifluoromethylsulfonyl)phenyl groups attached to the cyclopropane ring, enough to compensate the opposite effect of the electron-donating mono-, bis-, or tris(octyloxy)phenyl group

Synthesis of thienyl analogues of PCBM and investigation of morphology of mixtures in P3HT

• Fukashi Matsumoto,
• Kazuyuki Moriwaki,
• Yuko Takao and
• Toshinobu Ohno

Beilstein J. Org. Chem. 2008, 4, No. 33, doi:10.3762/bjoc.4.33

• further purified by reprecipitation from methanol. In general, the resulting products of the above synthesis process contain the isomers of [5,6]fulleroid (methanoannulene-type bonding) and [6,6]methanofullerene (cyclopropane bonding) [23]. These isomers are clearly distinguishable by the 13C NMR chemical

Trifluoromethyl ethers – synthesis and properties of an unusual substituent

• Frédéric R. Leroux,
• Baptiste Manteau,
• Jean-Pierre Vors and
• Sergiy Pazenok

Beilstein J. Org. Chem. 2008, 4, No. 13, doi:10.3762/bjoc.4.13

• improved thermal stabilities relative to the inhalation anesthetics in common use at that time (cyclopropane and ether), like the halo ether anesthetic Fluoroxene (Fluoromar®, F3C-H2C-O-CH=CH2). Numerous analogues [13] were prepared and evaluated (Table 1). Meanwhile, cyclic analogues bearing the

Allylsilanes in the synthesis of three to seven membered rings: the silylcuprate strategy

• Asunción Barbero,
• Francisco J. Pulido and
• M. Carmen Sañudo

Beilstein J. Org. Chem. 2007, 3, No. 16, doi:10.1186/1860-5397-3-16

• -cyclopropane moiety, from open chain allylsilanes in just one step. The high stereocontrol associated to the ring formation allows the synthesis of enantiomerically pure spiro-tricyclic alcohols containing an angular OH-group, such as 38 (Scheme 7). [20] The use of reagents different from organoaluminun

Contemporary organosilicon chemistry

• Steve Marsden

Beilstein J. Org. Chem. 2007, 3, No. 4, doi:10.1186/1860-5397-3-4

• fluorination, cyclopropane chemistry and the development of silicon-containing drug candidates should be available shortly. Be sure to check back to keep abreast of the latest developments as the Series grows. Steve Marsden Guest Editor

Cimicifoetisides A and B, two cytotoxic cycloartane triterpenoid glycosides from the rhizomes of Cimicifuga foetida, inhibit proliferation of cancer cells

• Li-Rong Sun,
• Chen Qing,
• Yan-Li Zhang,
• Shu-Yu Jia,
• Zhong-Rong Li,
• Shen-Ji Pei,
• Ming-Hua Qiu,
• Michael L. Gross and
• Samuel X. Qiu

Beilstein J. Org. Chem. 2007, 3, No. 3, doi:10.1186/1860-5397-3-3

• revealed its identity as a member of the cycloartane group of triterpene glycosides, a characteristic and distinguishable chemical marker of Cimicifuga plants. [6] In the 1H-NMR spectrum (Table 1), the characteristic cyclopropane methylene signals at δH 0.22 and 0.46 (each 1H, d, J = 3.0 Hz); eight methyl