Acid- mediated reactions under microfluidic conditions: A new strategy for practical synthesis of biofunctional natural products

• Katsunori Tanaka and
• Koichi Fukase

Beilstein J. Org. Chem. 2009, 5, No. 40, doi:10.3762/bjoc.5.40

• reactive sialyl donors having C-5 cyclic imides (Table 1), especially N-phthalimide 1a, by virtue of the “fixed-dipole moment effects” (α-only, 92% on 50 mg scale) [41]. The scale-up in a batch process, however, significantly decreased the yield and selectivity. Thus, a 100 mg scale reaction of 1a gave

Mitomycins syntheses: a recent update

• Jean-Christophe Andrez

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

• [4.1.0] ring system. It was necessary to methanolyse the lactone 69 prior to removal of the phthalimide with methyl hydrazine, which occurred with concomitant cyclization to form penultimate intermediate 70. The final ring closure was realized by treatment with camphorsulfonic acid to form lactam 71 in

Synthesis and enzymatic evaluation of 2- and 4-aminothiazole- based inhibitors of neuronal nitric oxide synthase

• Graham R. Lawton,
• Haitao Ji,
• Pavel Martásek,
• Linda J. Roman and
• Richard B. Silverman

Beilstein J. Org. Chem. 2009, 5, No. 28, doi:10.3762/bjoc.5.28

• diastereomers was formed, but both were oxidized to α-bromoketone 12. Condensation with thiourea gave the 2-aminothiazole (13). Diprotection of the amine with Boc groups and deprotection of the TBS ether gave trans-alcohol 15. A Mitsunobu reaction was used to install a nitrogen atom in the form of a phthalimide

• does not need to be diprotected to allow the Mitsunobu reaction with phthalimide as the nucleophile to proceed (28a-c). This is presumably because the thiazole nitrogen is less nucleophilic. Cleavage of the phthalimide group gave amines 29a-c. The syntheses of 4a-c were completed by reductive amination

• (2.5 equiv), DMAP, THF, rt, 16 h; viii) TBAF, THF, rt 16 h; ix) PPh3, DIAD, phthalimide, THF, rt, 16 h; x) H2NNH2 (aq), MeOH, rt, 16 h, then 2N HCl, rt, 30 min. Synthesis of compound 3. i) 4-chlorobenzylchloride, EtOH, reflux, 4 h; ii) Boc2O, TEA, MeOH, 3 h; iii) 1 N NaOH, MeOH, rt, 4 h; iv) EDC, HOBt

N-Arylation of amines, amides, imides and sulfonamides with arylboroxines catalyzed by simple copper salt/EtOH system

• Zhang-Guo Zheng,
• Jun Wen,
• Na Wang,
• Bo Wu and
• Xiao-Qi Yu

Beilstein J. Org. Chem. 2008, 4, No. 40, doi:10.3762/bjoc.4.40

• -containing substrates with arylboroxine conducted in protic solvent only with the use of copper salts has not been explored previously. Results and Discussion Firstly, we chose phthalimide and phenylboroxine as model substrates to optimize the catalytic conditions (copper source, temperature, solvent, amount

• system. Being of lower toxicity, easier to process and environmentally benign, EtOH was chosen as reaction medium for this coupling reaction. The ratio of phthalimide to arylboroxine and the amount of Cu(OTf)2 are both important factors for this coupling reaction (Table 4, entries 1–7). We found that

• variety of substrates bearing methyl- and bromophenylboroxines using phthalimide under our generalized conditions (Table 5, entries 2–3). The results demonstrated that there was little difference between the effect of an electron-rich aryl ring and an electron-deficient aryl ring in this cross-coupling

Combining two-directional synthesis and tandem reactions, part 11: second generation syntheses of (±)-hippodamine and (±)-epi-hippodamine

• Annabella F. Newton,
• Martin Rejzek,
• Marie-Lyne Alcaraz and
• Robert A. Stockman

Beilstein J. Org. Chem. 2008, 4, No. 4, doi:10.1186/1860-5397-4-4

• acrylate as the cross-metathesis coupling partner. In fact, due to the non-co-ordinating nature of ethyl acrylate (in comparison to acrylonitrile) and the inert phthalimide group, this reaction proved to be an outstanding success, delivering diester 6 in 88% yield over one step after a five day reaction in

• -metathesis reaction is shown in Scheme 2. Having refined our synthesis of diester 7 by providing a shortened synthesis of its precursor, we decided to see if we could attain a synthesis of this common intermediate for the synthesis of both hippodamine and epi-hippodamine without the use of the phthalimide