Marine Puupehenone and Puupehedione: Synthesis and Future Perspectives.

Puupehenone and puupehedione are natural products isolated from marine organisms. These compounds display a broad spectrum of biological activities, the in vitro antitubercular activity of puupehenone being a stand out, and are equipped with an interesting structural complexity. These products have served to stimulate the continual interest of the synthetic community. The first part of this article is a review of their total synthesis, using natural compounds which have the potential to be transformed into these marine compounds as starting materials; the synthetic routes employed to generate the basic skeleton; and the advances made to synthesize the pyran C ring with the required diastereoselectivity to obtain the natural products. Finally, this perspective shows a personal reflection of the authors on a possible unified and efficient retrosynthetic route that could allow easy access to these natural products, as well as their epimers at the C8 carbon and which could be used to address future biological issues in the production of pharmacologically active compounds.

Unifying the Synthesis of a Whole Family of Marine Meroterpenoids through a Biosynthetically Inspired Sequence of 1,2-Hydride and Methyl Shifts as Key Step.

Marine meroterpenoids have attracted a great deal of attention from synthetic research groups due to their attractive and varied biological activities and their unique and diverse structures. In most cases, however, further biological studies have been severely limited mainly to the scarcity of natural supply and because almost none of the reported syntheses methods has enabled unified access for a large number of marine meroterpenoids with aureane and avarane skeletons. Based on our previous publications and the study of recent manuscripts on marine meroterpenoids, we have conceived a unified strategy for these fascinating marine compounds with aureane or avarane skeletons using available drimane compounds as starting materials. The key step is a biosynthetic sequence of 1,2-hydride and methyl shifts. This strategy is of great synthetic value to access marine meroterpenoids through easy chemical synthetic procedures. Finally, several retrosynthetic proposals are made for the future synthesis of several members of this class of meroterpenoids, focused on consolidating these 1,2-rearrangements as a versatile and unified strategy that could be widely used in the preparation of these marine meroterpenoids.

A Concise Diastereoselective Total Synthesis of α-Ambrinol.

(-)-cis-α-Ambrinol is a natural product present in ambergris, a substance of marine origin that has been highly valued by perfumers. In this paper, we present a new approach to its total synthesis. The starting material is commercially available α-ionone and the key step is an intramolecular Barbier-type cyclization induced by CpTiCl2, an organometallic compound prepared in situ by a CpTiCl3 reduction with Mn.

Divergent Strategy in Marine Tetracyclic Meroterpenoids Synthesis.

The divergent total synthesis strategy can be successfully applied to the preparation of families of natural products using a common late-stage pluripotent intermediate. This approach is a powerful tool in organic synthesis as it offers opportunities for the efficient preparation of structurally related compounds. This article reviews the synthesis of the marine natural product aureol, as well as its use as a common intermediate in the divergent synthesis of other marine natural and non-natural tetracyclic meroterpenoids.

A Concise Route for the Synthesis of Tetracyclic Meroterpenoids: (±)-Aureol Preparation and Mechanistic Interpretation.

A new concise general methodology for the synthesis of different tetracyclic meroterpenoids is reported: (±)-aureol (1), the key intermediate of this general route. The synthesis of (±)-aureol (1) was achieved in seven steps (28% overall yield) from (±)-albicanol. The key steps of this route include a C-C bond-forming reaction between (±)-albicanal and a lithiated arene unit and a rearrangement involving 1,2-hydride and 1,2-methyl shifts promoted by BF3•Et2O as activator and water as initiator.

Identification of terpenes and essential oils by means of static headspace gas chromatography-ion mobility spectrometry.

Static headspace gas chromatography-ion mobility spectrometry (SHS GC-IMS) is a relatively new analytical technique that has considerable potential for analysis of volatile organic compounds (VOCs). In this study, SHS GC-IMS was used for the identification of the major terpene components of various essential oils (EOs). Based on the data obtained from 25 terpene standards and 50 EOs, a database for fingerprint identification of characteristic terpenes and EOs was generated utilizing SHS GC-IMS for authenticity testing of fragrances in foods, cosmetics, and personal care products. This database contains specific normalized IMS drift times and GC retention indices for 50 terpene components of EOs. Initially, the SHS GC-IMS parameters, e.g., drift gas and carrier gas flow rates, drift tube, and column temperatures, were evaluated to determine suitable operating conditions for terpene separation and identification. Gas chromatography-mass spectrometry (GC-MS) was used as a reference method for the identification of terpenes in EOs. The fingerprint pattern based on the normalized IMS drift times and retention indices of 50 terpenes is presented for 50 EOs. The applicability of the method was proven on examples of ten commercially available food, cosmetic, and personal care product samples. The results confirm the suitability of SHS GC-IMS as a powerful analytical technique for direct identification of terpene components in solid and liquid samples without any pretreatment. Graphical abstract Fingerprint pattern identification of terpenes and essential oils using static headspace gas chromatography-ion mobility spectrometry.

Influencia de la calidad embrionaria y seminal en el síndrome del embrión evanescente / Embryo and seminal quality and its influence on the vanishing embryo syndrome

Introducción. La evanescencia embrionaria consiste en la pérdida espontánea de uno o más embriones durante una gestación múltiple sin que el embarazo se interrumpa. Nuestros objetivos fueron: determinar la tasa de evanescencia en mujeres con embarazos múltiples concebidos por microinseminación espermática (ICSI: Intracytoplasmic Sperm Inyection), analizar la evolución de estos embarazos y relacionar la presencia de este fenómeno con posibles causas cuantificables en laboratorio como la calidad embrionaria y la calidad seminal, así como con la edad de la mujer. Material y métodos. Estudio retrospectivo de 145 embarazos múltiples de ciclos de ICSI realizados entre el 1/01/2004 y el 31/12/2008, las pacientes fueron divididas en dos grupos (112 no evanescentes y 33 con saco/s evanescentes). Se realizó seguimiento ecográfico de las embarazadas y los parámetros se recogieron de la base de datos del centro. Posteriormente realizamos un estudio de casos-controles histórico para analizar los resultados neonatales de los embarazos simples procedentes de evanescentes, comparando con un grupo control de nacimientos procedentes de embarazos simples obtenido mediante técnicas de reproducción asistida (TRA) en nuestro centro que fueron registrados en el mismo período de estudio (n=163). Resultados. La tasa de evanescencia se situó en un 22,7%, siendo de un 17,5% en embarazos gemelares y de un 50% en embarazos triples. La evanescencia en los embarazos múltiples fue significativamente menor en el grupo con dos sacos gestacionales que en el grupo con tres o más sacos gestacionales (p<0,001). Los resultados perinatales de los nacidos vivos en embarazos con evanescencia fueron similares a los obtenidos en nacidos procedentes de embarazos inicialmente simples. La tasa de embriones de buena calidad fue significativamente mayor en el grupo sin evanescentes (p<0,001). No se observaron diferencias en términos de edad y de calidad seminal entre los grupos de estudio. Conclusiones. La tasa de evanescencia embrionaria aumenta significativamente en los embarazos de más de dos sacos gestacionales, existiendo una relación entre este fenómeno y la calidad de la transferencia embrionaria (AU)

Background. The vanishing embryo phenomenon is defined as the spontaneous loss of one or more embryos in a multiple pregnancy without its interruption. The aim of this study was to determine the rate of vanishing embryo syndrome in women with multiple pregnancies conceived by Intracytoplasmic Sperm Injection (ICSI), to analyse the evolution of these pregnancies, and to find a relationship with possible causes, such as embryo and seminal quality. Material and methods. A retrospective analysis was performed of 145 multiple pregnancies conceived by ICSI, from January 2004 to December 2008. They were divided in two groups (112 without vanishing syndrome and 33 with any embryo suffering from vanishing syndrome). We then carried out a case-control study in order to compare the neonatal results of single pregnancies with vanishing embryo syndrome. We carried out transvaginal ultrasound monitoring until 12weeks of gestation. The data were obtained from the centre data base. Results. Vanishing embryo syndrome was observed in 22.7% of our patients, with 17.5% of cases being observed in twin pregnancies, and 50% in triple pregnancies. The vanishing embryo rate in multiple pregnancies was significantly lower in the group with two gestational sacs than in the group with three or more gestational sacs (P<.001). The rate of good quality embryos was significantly higher in the group without vanishing embryos (P<.001). No differences were observed in terms of age and seminal quality among study groups. Perinatal outcomes of live births were similar in both groups. Conclusion. Vanishing embryos rate seems to increase in pregnancies with over two gestational sacs. We observed a relationship between this syndrome and embryo transfer quality (AU)