Esters are ubiquitous. Most naturally occurring fats and oils are the fatty acid esters of glycerol. Esters with low molecular weight are commonly used as fragrances and found in essential oils and pheromones. Phosphoesters form the backbone of DNA molecules. Nitrate esters, such as nitroglycerin, are known for their explosive properties, while polyesters are important plastics, with monomers linked by ester moieties.
The chemical formulas of organic esters are typically written in the format of RCO2R', where R and R' are the hydrocarbon parts of the carboxylic acid and alcohol, respectively. For example butyl acetate, derived from butanol and acetic acid would be written CH3CO2C4H9. Alternative presentations are common including BuOAc and CH3COOC4H9.
Cyclic esters are called lactones, regardless of whether they are derived from an organic or an inorganic acid. One example of a (organic) lactone is gamma-valerolactone.
Reagents are known that drive the dehydration of mixtures of alcohols and carboxylic acids. One example is the Steglich esterification, which is a method of forming esters under mild conditions. The method is popular in peptide synthesis, where the substrates are sensitive to harsh conditions like high heat. DCC (dicyclohexylcarbodiimide) is used to activate the carboxylic acid to further reaction. DMAP (4-dimethylaminopyridine) is used as an acyl-transfer catalyst. :
Another method for the dehydration of mixtures of alcohols and carboxylic acids is the Mitsunobu reaction: :RCO2H + R'OH + P(C6H5)3 + R2N2 → RCO2R' + OP(C6H5)3 + R2N2H2
Carboxylic acids can be esterified using diazomethane: :RCO2H + CH2N2 → RCO2CH3 + N2 Using this diazomethane, mixtures of carboxylic acids can be converted to their methyl esters in near quantitative yields, e.g., for analysis by gas chromatography. The method is useful in specialized organic synthetic operations but is considered too expensive for large scale applications.
The reactions are irreversible simplifying work-up. Since acyl chlorides and acid anhydrides also react with water, anhydrous conditions are preferred. The analogous acylations of amines to give amides are less sensitive because amines are stronger nucleophiles and react more rapidly. This method is employed only for laboratory-scale procedures, as it is expensive.
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Name | Ester Dean |
---|---|
Background | solo_singer |
Born | December 15, 1986 |
Instrument | Vocals |
Genre | R&B;, hip hop, pop |
Occupation | Singer-songwriter, rapper, record producer |
Label | Interscope, Polydor, Zone 4 |
Associated acts | Katy Perry, Monica, Chris Brown, Soulja Boy Tell 'Em, Ciara, Usher, Lloyd, Nicki Minaj, Rihanna |
Url | EsterDean.com |
Ester Renay Dean (frequently seen as Esther Dean), born on December 15, 1986 is an American singer-songwriter, and record producer signed to Zone 4 Records/Interscope Records. She is most notable for her dual appearance on Rio: Music From The Motion Picture (2011) and her 2009 US hit single "Drop It Low", which featured singer Chris Brown. Dean has also written songs with many artists including Nicki Minaj, Katy Perry, Mary J Blige, Christina Aguilera, Ciara, Nicole Scherzinger, Usher, Girlicious, Rihanna, R. Kelly, Britney Spears, and Soulja Boy Tell 'Em.
Dean has co-written songs featured on the Step Up 3D Original Motion Picture Soundtrack (2010) and (2010). She also co-wrote "Super Bass", a bonus track for Nicki Minaj's debut album Pink Friday (2011). The song was received well, with many fans stating it was better than some of the main tracks, and should have been on the standard edition of the album. It was released as a single and has achieved the position of number ten on the Hot 100, making it Minaj's first top ten placement as a lead artist. The song's popularity is also indicated as part of the title of a UK Deluxe edition of the album, Pink Friday (Super Bass Edition). Dean has a dual appearance on Rio: Music From The Motion Picture (2011) with "Let Me Take You To Rio" and "Take You To Rio".
She is working on her debut studio album set to be released in 2011.
Category:1986 births Category:Living people Category:2000s singers Category:2010s singers Category:American pop singers Category:American rhythm and blues singers Category:Hip hop singers Category:English-language singers Category:American record producers
This text is licensed under the Creative Commons CC-BY-SA License. This text was originally published on Wikipedia and was developed by the Wikipedia community.
Name | Chris Brown |
---|---|
Background | solo_singer |
Birth name | Christopher Maurice Brown |
Born | May 05, 1989 |
Origin | Tappahannock, Virginia, United States |
Genre | R&B;, pop, urban, hip hop |
Occupation | Singer-songwriter, dancer, rapper, actor |
Voice type | Tenor |
Years active | 2005–present |
Label | Jive, Zomba |
Associated acts | Tyga, Game, Lil Wayne, Bow Wow, T.I., Big Sean |
Url |
Brown's second studio album, Exclusive was released worldwide in November 2007. It spawned two successful singles; his second U.S. number one hit, "Kiss Kiss" featuring T-Pain and "With You", which peaked at number two on the Billboard Hot 100. Brown has released a deluxe version of his album called The Forever Edition. The first single from it, "Forever", was released in May 2008 and reached number two on Billboard Hot 100. Exclusive has been certified Platinum by the RIAA. and his dance routines have been compared to the likes of Michael Jackson.
In 2009, Brown pleaded guilty to felony assault of singer and then-girlfriend Rihanna, and was sentenced to five years probation and six months of community service. The case received widespread media attention and negatively affected his career as a singer and all-around entertainer.
At the age of 13, Brown was discovered by a local production team who visited his father's gas station while searching for new talent. The singer then, moved to New York.
The negotiations with Def Jam lasted two months until Davis lost her job due to a corporate merger. Brown then asked her to be his manager and Davis accepted, starting to "promote" the singer to labels such as Jive Records, J-Records and Warner Bros. Records. According to Mark Pitts in an interview with HitQuarters, Davis presented Brown with a video recording and Pitts' reaction was: "I saw the potential ... I didn’t love all the records, but I loved his voice. It wasn’t a problem because I knew that he could sing, and I knew how to make records." Brown ultimately choose Jive, due to its successful work with then-young acts such as Britney Spears and Justin Timberlake. Brown claims, "I picked Jive because they had the best success with younger artists in the pop market, [...] I knew I was going to capture my African American audience, but Jive had a lot of strength in the pop area as well as longevity in careers." Brown also made some input on the album, receiving co-writing credits of five tracks. The whole album took less than eight weeks to produce, Self-titled Chris Brown, it debuted at number two on the Billboard 200 with first week sales of 154,000 copies. Chris Brown was a relative commercial success with the time; selling over two million copies in the United States—where it was certified two times platinum by the RIAA—and three million copies worldwide. The album's lead single, "Run It!", made Brown the first male act (since Montell Jordan in 1995) to have his debut single to reach the summit of the Billboard Hot 100—later remaining for four additionally weeks.
On June 13, 2006, Brown released a DVD entitled, Chris Brown's Journey, which shows footage of him traveling in England and Japan, getting ready for his first visit to the Grammy Awards, behind the scenes of his music videos and bloopers.
On August 17, 2006 to further promote the album, Brown began his major co-headlining tour, The Up Close and Personal Tour. Due to the tour, production for his next album was pushed back two months. St. Jude Children's Research Hospital received $10,000 in ticket proceeds from Brown's 2006 "Up Close & Personal" tour. Brown was also the opening act for R&B; singer Beyoncé Knowles on the Australian leg of her The Beyoncé Experience tour.
Shortly after ending his summer tour with Ne-Yo, Brown quickly began production for his second studio album, Exclusive, which was released in November 2007. The album debuted at number four on the Billboard 200, selling 294,000 copies in its first week. It has sold 1.9 million copies in the United States.
According to MTV News, Brown stated: "I am still going to keep it so my younger fans can continue to listen to my music, but I got a couple of joints on there that's for some of the older people." The album's first single, "Wall to Wall", debuted on the Billboard Hot 100 at number 96, and peaked at number 79 and number 22 on the Billboard R&B; and Hip-Hop Chart becoming his lowest charting song to date. "Kiss Kiss", featuring and produced by T-Pain, was released as the second single. "Kiss Kiss," became more successful surpassing the success of "Wall To Wall," reaching number one on the U.S. Billboard Hot 100 to become Chris' second number one single and his highest chart peak since "Run It!" in 2005.
On December 4, 2007, Brown released the third single from "Exclusive," entitled "With You", a song produced by Stargate. "With You" reached number two on the Billboard Hot 100 and had entered the charts in various countries around the world, becoming one of Brown's most successful released to date, entering the top ten in New Zealand, Singapore, Canada, the United States, Cyprus, Ireland, France, the United Kingdom, Malaysia, and Australia.
Brown re-released Exclusive on June 3, 2008 as a deluxe edition, renamed Exclusive: The Forever Edition, seven months after the release of the original version. The re-released version featured four new tracks, including the single "Forever" which reached number two on Billboard Hot 100.
In support of the album, Brown embarked on his The Exclusive Holiday concert tour, visiting over thirty venues in United States. He started the tour in Cincinnati, Ohio, on December 6, 2007 and concluded it on February 9, 2008 in Honolulu, Hawaii. The documented footage was released on June 3, 2008 as the double disc of Exclusive: The Forever Edition. He performed "With You" at the BET Awards '08 in June 2008. He was then joined by Ciara to dance with him to a snippet of the song "Take You Down".
Brown, alongside The Game, is featured on Nas' untitled album on "Make the World Go Round", co-produced by The Game and Cool & Dre. He is also featured alongside Sean Garrett for Ludacris' single "What Them Girls Like" off Ludacris's album Theater of the Mind. He was also featured on T-Pain's third single "Freeze" off T-Pain's new album Thr33 Ringz. Brown was named the top artist of 2008 by Billboard magazine. Brown lent his efforts to promote the Math-A-Thon benefiting that hospital by starring as the host in a film to promote it. Brown released his single "Take You Down" in January 2009 in the UK and Ireland.
"Yeah 3x" was released as the album's lead single on October 25, 2010. The song peaked at number 15 in the United States and Canada. It also charted in the top five in Australia and New Zealand, receiving platinum certifications in both countries. "Look at Me Now" featuring Lil Wayne and Busta Rhymes, was released as the second single in January 2011. Most recently, it was revealed F.A.M.E will be released in March 2011. In support of the album, Brown will headline the F.A.M.E Tour, starting in Australia in April 2011.
Brown was also featured in UK rapper Chipmunk's single Champion, which was released in February 6, 2011 in United Kingdom. He was additionally asked by Tionne "T-Boz" Watkins of the girl group TLC to be featured on her new album, Still Cool. Most recently Brown was tabbed to perform at BET Awards 2011 airing on June 26, 2011.
On March 5, 2009, Brown was charged with felony assault and making criminal threats. He was arraigned on April 6, 2009, and pleaded not guilty to one count of assault and one count of making criminal threats. On June 22, 2009, Brown pleaded guilty to a felony and accepted a plea deal of community labor and five years' formal probation. Domestic violence counseling is also part of the deal by Judge Patricia Schnegg in court. Several organizations against domestic violence expressed criticism over the plea deal, advocating the punishment was not severe enough for the crime; the level of Brown's influence over youth also came under scrutiny. Brown said he wanted to speak out earlier about the case but was advised by his attorney not to until the legal ramifications were settled.
On September 2, 2009, Brown spoke about the domestic violence case in a pre-recorded Larry King Live interview, his first public interview about the matter. He was accompanied in the interview by his mother and attorney Mark Geragos, as he discussed growing up in a household rampant with domestic violence; his mother had been repeatedly assaulted by his stepfather. Brown said of hearing details of what transpired the night of his own assault, his physical altercation with Rihanna, "I'm in shock, because, first of all, that's not who I am as a person, and that's not who I promise I want to be." Following criticism of saying he did not remember, Brown later said in a statement, "Of course I remember what happened. Several times during the interview, my mother said that I came to her right afterwards and told her everything." Brown said despite this, "[that night] was and still is a blur". In June 2010, Brown's application for a visa to enter the UK was refused on the grounds of him "being guilty of a serious criminal offence." Brown had been planning to do a tour of British cities as part of a European tour but Sony stated that due to "issues surrounding his work visa" the tour was to be postponed. The British Home Office confirmed that Brown was refused permission on the grounds of being guilty of a serious criminal offence – his assault on ex-girlfriend Rihanna.
On March 22, 2011, after his first performance of "Yeah 3x" and a contentious interview with Roberts on Good Morning America at the Times Square Studios where he was asked about the Rihanna situation and restraining order, Brown allegedly became violent in his dressing room during a commercial break before his second performance ending that day's program, and threw an object at a window overlooking Times Square, causing damage to the window. Brown then took off his shirt and after several angry confrontations with the segment producer, other show staff and building security, left the building shirtless. Following the incident, Brown left a message on Twitter saying, "I'm so over people bring this past s**t up!! Yet we praise Charlie Sheen and other celebs for there[sic] bulls**t." It was deleted moments later.
Category:1989 births Category:2000s singers Category:2010s singers Category:2010s rappers Category:Actors from Virginia Category:African American film actors Category:African American rappers Category:African American singers Category:American child singers Category:American dance musicians Category:African American dancers Category:Dance-pop Category:American male singers Category:American music video directors Category:American pop singers Category:American rhythm and blues singers Category:American people convicted of assault Category:English-language singers Category:Hip hop singers Category:Jive Records artists Category:Living people Category:Musicians from Virginia Category:Sony BMG artists Category:World Music Awards winners Category:American film producers
This text is licensed under the Creative Commons CC-BY-SA License. This text was originally published on Wikipedia and was developed by the Wikipedia community.
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