Heterogeneous photocatalysis in flow chemical reactors

• Christopher G. Thomson,
• Ai-Lan Lee and
• Filipe Vilela

Beilstein J. Org. Chem. 2020, 16, 1495–1549, doi:10.3762/bjoc.16.125

Recent synthesis of thietanes

• Jiaxi Xu

Beilstein J. Org. Chem. 2020, 16, 1357–1410, doi:10.3762/bjoc.16.116

• III (155) was isolated from the leaves of the European yew tree Taxus baccata L. in a significant yield and was applied as starting material for the semisynthesis of 5(20)-thiadocetaxel 158. First, the compound was converted into the corresponding bromomethyloxirane derivative 156, which generated the

• yields as well. The compounds were used for the semisynthesis of further sulfur derivatives of taxoids by first converting them into the acetal-protected oxiranemethyl mesylate derivative 164. After the treatment of compound 164 with KSAc, the mesylate 165 generated the corresponding thietane-fused

Synthetic terpenoids in the world of fragrances: Iso E Super^® is the showcase

• Alexey Stepanyuk and
• Andreas Kirschning

Beilstein J. Org. Chem. 2019, 15, 2590–2602, doi:10.3762/bjoc.15.252

• ) from which the acetate (26) can be prepared by semisynthesis [6]. Obviously, nature served as starting point and guideline for creating scents and these lists reveal, that terpenes, particularly mono- and sesquiterpenes, have played a rather dominant role in the fragrance industries [6]. Over the last

A semisynthesis of 3'-O-ethyl-5,6-dihydrospinosyn J based on the spinosyn A aglycone

• Kai Zhang,
• Shenglan Liu,
• Anjun Liu,
• Hongxin Chai,
• Jiarong Li and
• Lamusi A

Beilstein J. Org. Chem. 2017, 13, 2603–2609, doi:10.3762/bjoc.13.257

• , spinetoram is widely used in agriculture and food storage. This work reports a 7-step semisynthesis of 3'-O-ethyl-5,6-dihydrospinosyn J from spinosyn A aglycone. The C9–OH and C17–OH of the aglycone are successively connected to 3-O-ethyl-2,4-di-O-methylrhamnose and D-forosamine after selective protection

• opportunities to synthesize spinosyn analogues and rhamnose derivatives. Keywords: 3-O-ethyl-2,4-di-O-methylrhamnose; protecting groups; semisynthesis; spinetoram; spinosyn A; Introduction Spinosyns, a large family of secondary metabolites produced by aerobic fermentation of Saccharopolyspora spinosa, are a

• also be used to synthesize the derivatives of rhamnose. Semisynthesis of 3'-O-ethyl-5,6-dihydrospinosyn J The C9–OH and C17–OH groups of the aglycone have similar activity, so different protection strategies are required for the hydroxy groups (Scheme 5). According to Martynow’s work [34], C9–OH can be

The chemistry and biology of mycolactones

• Matthias Gehringer and
• Karl-Heinz Altmann

Beilstein J. Org. Chem. 2017, 13, 1596–1660, doi:10.3762/bjoc.13.159

Aqueous semisynthesis of C-glycoside glycamines from agarose

• Juliana C. Cunico Dallagnol,
• Alexandre Orsato,
• Diogo R. B. Ducatti,
• Miguel D. Noseda,
• Maria Eugênia R. Duarte and
• Alan G. Gonçalves

Beilstein J. Org. Chem. 2017, 13, 1222–1229, doi:10.3762/bjoc.13.121

• reductive amination to accomplish such a synthesis through a short protecting-group-free route and (c) the compatibility of the starting material and all reaction conditions to the aqueous media, here we present the aqueous semisynthesis of mono- and disaccharide glycamines obtained by hydrolysis and

• obtain C-glycofuranose-containing glycamines through a short, protecting-group-free and aqueous-based semisynthesis. Our present study also addressed the obstacles frequently faced in reductive amination of carbohydrates (such as byproduct accumulation and purification issues) and contributed to provide

Preparation of new alkyne-modified ansamitocins by mutasynthesis

• Kirsten Harmrolfs,
• Lena Mancuso,
• Binia Drung,
• Florenz Sasse and
• Andreas Kirschning

Beilstein J. Org. Chem. 2014, 10, 535–543, doi:10.3762/bjoc.10.49

• ). From here a set of tailoring enzymes transform proansamitocin into the bioactive final metabolites 3–5 following a predetermined logic that is only flexible in part (Scheme 1). We extended these studies by combining mutasynthesis and semisynthesis and thus accessed four new tumor specific folic acid

• be achieved by benzylic positioning as well as by choosing aryl bromides A (Scheme 3) that can be modified to the corresponding aryl alkynes C by cross coupling chemistry. Previously, we successfully utilized this combination of mutasynthesis and semisynthesis for 19-brominated ansamitocin

• . Noteworthy 27b is inactive which we ascribe to the fact that it may have dimerized back to 27a. Conclusion The combination of mutasynthesis and semisynthesis has great potential for the production of more selective ansamitocin derivatives. In this work we pursued different options to prepare ansamitocin

Unprecedented deoxygenation at C-7 of the ansamitocin core during mutasynthetic biotransformations

• Tobias Knobloch,
• Gerald Dräger,
• Wera Collisi,
• Florenz Sasse and
• Andreas Kirschning

Beilstein J. Org. Chem. 2012, 8, 861–869, doi:10.3762/bjoc.8.96

• pharmaceuticals because of their structural complexity and the difficulties associated with accessing analogues for structure–activity relationship studies. Total synthesis approaches are still a tour de force and are hardly employed, while commonly semisynthesis as well as biotechnological approaches are widely

Efficient oxidation of oleanolic acid derivatives using magnesium bis(monoperoxyphthalate) hexahydrate (MMPP): A convenient 2-step procedure towards 12-oxo-28-carboxylic acid derivatives

• Jorge A. R. Salvador,
• Vânia M. Moreira,
• Rui M. A. Pinto,
• Ana S. Leal and
• José A. Paixão

Beilstein J. Org. Chem. 2012, 8, 164–169, doi:10.3762/bjoc.8.17

• triterpenoids bearing a γ-lactone function, either isolated from natural sources or obtained by semisynthesis, have shown interesting biological activities [12][13][14]. From the synthetic point of view, the oxidative 28,13β-lactonization allows the preparation of 12α-hydroxyoleananes with a protected 28