Judul: Telaah Mekanisme Oksidasi Langsung Asetal Menjadi Ester dalam Sintesis Total Masoilakton secara In Silico
Abstrak: Reaksi oksidasi langsung asetal menjadi ester di sini adalah reaksi pengubahan senyawa asetal menjadi ester secara langsung dengan pereaksi H2O2/HCl dalam metanol. Reaksi ini dapat digunakan dalam sintesis total masoilakton dan belum pernah ditelaah secara in silico. Berdasarkan perhitungan PM3, reaksi oksidasi langsung tersebut dimulai oleh transfer hidrida dari atom karbon asetal ke atom klorin HOCl pada keadaan multiplisitas triplet, disusul dengan adisi H2O pada karbokation asetal, dan pelepasan salah satu gugus metoksi asetal membentuk ester terprotonasi. Transfer proton termediasi metanol menjadi bagian penting dari reaksi ini. Transfer hidrida yang terjadi di awal mekanisme reaksi terjadi secara nonadiabatik sehingga tidak membutuhkan induksi cahaya.
Keyword: HOCl, masoilakton, oksidasi, transfer hidrida, transfer nonadibatik

Judul: Studi In Silico Mekanisme Reaksi Aldol Asimetrik (E)-Heks-2-enal dan Diketena dengan Katalis Al(OiPr)3-(S)-BINOL untuk Sintesis (R)-Masoilakton C-10.
Abstrak: (R)-Masoilakton C-10 adalah komponen utama penyusun cita rasa dan aroma minyak masohi, salah satu hasil hutan bukan kayu asal Papua, Indonesia. Sintesis asimetrik ringkas senyawa ini telah dilaporkan dengan tahapan kunci ialah adisi aldol berkataliskan Ti(OiPr)4-(S)-BINOL antara (E)-heks-2-enal dan diketena. Penelitian ini mengkaji secara komputasi reaksi tersebut menggunakan katalis Al(OiPr)3-(S)-BINOL yang lebih sederhana, dengan metode semiempiris MNDO dan PM3. Pendekatan ini dimaksudkan sebagai prediksi struktur keadaan transisi (TS) untuk katalis Ti(OiPr)4-(S)-BINOL (metode DFT (M06(3-21G(d)). Kompleks [Ti(OiPr)2(S-BINOL)] berbentuk trigonal antiprismatik, sedangkan [Al(OiPr)(S-BINOL)] tetrahedral. Dua mekanisme adisi diusulkan dan ekses enantiomerik sangat tinggi [99.8% dengan metode MNDO] ketika anion enolat dari diketena mengadisi aldehida yang telah terkompleks pada katalis. Hasil ini menunjukkan peluang katalis Al(OiPr)3-(S)-BINOL menggantikan Ti(OiPr)4-(S)-BINOL untuk kendali stereokimia. Reaksi berlangsung eksoterm. Mekanisme ini masih perlu diuji pada sistem berpelarut. Demikian pula struktur TS dugaan untuk katalis Ti(OiPr)4-(S)-BINOL masih perlu dikonfirmasi.
Keyword: BINOL, keadaan transisi, masoilakton, Papua, semiempiris

Judul: Phylogeography and Species Limits in the Papuan White Snake (Micropechis ikaheka) (Reptilia: Serpentes: Elapidae)
Abstrak: Papua white snake, Micropechis ikaheka, has been distingushed into two subspecies M.i. ikaheka and M.i. fasciatus. However, due to lack of data on their morphology, distribution and ecology, both subspecies often ignored in scintific discussions and refers only byas , Micropechis ikaheka. This study was designed to document the differences between M.i. ikaheka and M.i fasciatus by using scales characteristics and reproductive organ or hemipenes. The study also examine, zoogeography, habitat, diet and cannibalism of both subspecies to better understanding the the ecology of one of the most venomous snakes in the world. This study consists of three topics with method and also different in the size samples, respectively. The first study is the histology and microtopography of the skin were studied using paraffin method and Scanning Electron Microscope (SEM). The second is the hemipenis were examined by following Myers and Cadle (2003), and Zaher and Prudente (2003). The third is the abdominal surgery was carried out to document diet type and the investigate phenomenon of cannibalism in the snake. Specimens for this study came from the collection from Museum Zoologicum Bogoriense (MZB) and Universitas Negeri Papua’s Laboratory (LZU). The research result also indicated that the markers of skin and hemipenis described the same structure and microornamentation in all M. ikaheka groups being compared. Based specimens examined morphological descriptions do not s support the further differentiation in Micropechis. In short, two markers that used in this study could not sufficiently indicate the differences in the level of species and subspecies of M. ikaheka. The study, however, were able to delineate zoogeography and skin color patterns, which fall into four groups: M. i. ikaheka; M. i. fasciatus. M. i. ssp. “intermediate”; and M. i. ssp “black”. This study also revealed that color variations did not overlap in their geographic distribution. It is therefore, it suggested that environmental factors may contribute to the skin color variations. It also assumed that habitat discontinuous and biogeography factors may also cause the loss of the connection between the original populations (vicarians) or follow colonization events (dispersal). The examined of 22 stomach contents of M. ikaheka shows this species is carnivorous, and prey on vertebrates such as amphibians, fish, reptiles, and Mammals. These snakes are opportunistic predators since they prey on all that can be captured, but mainly reptiles (61.5%), followed by mammals and fish (both 15.4%), and amphibians (7.7%). Although categorized as terrestrial animal, the diet study showed that M. ikaheka snakes often go into the water to hunt for fish (the sample from Yapen island), including eel (the sample from Aru island). Based on prey items indentified, there is evidence that M. ikaheka is cannibal. At this time, there still no record on reason for cannibalism, but it is assumed that cannibalism was due to competition between populations and means to control population.
Keyword: geographic variation, white snake, papua